Alkyne-containing antiviral agents

ABSTRACT

The present invention discloses compounds of Formula (I), and pharmaceutically acceptable salts, thereof: 
     
       
         
         
             
             
         
       
     
     which inhibit coronavirus replication activity. The invention further relates to pharmaceutical compositions comprising a compound of Formula (I) or a pharmaceutically acceptable salt thereof, and methods of treating or preventing a coronavirus infection in a subject in need thereof, comprising administering to the subject a therapeutically effective amount of a compound of Formula (I) or a pharmaceutically acceptable salt thereof.

RELATED APPLICATION

This application claims the benefit of U.S. Provisional Application No.63/278,550, filed on Nov. 12, 2021. The entire teachings of the aboveapplication are incorporated herein by reference.

TECHNICAL FIELD

The invention relates to compounds and methods of inhibiting coronavirusreplication activity by targeting the 3C-Like protease (sometimesreferred to as “3CLpro”, “Main protease”, or “Mpro”) with atherapeutically effective amount of a 3C-Like protease inhibitor. Theinvention further relates to pharmaceutical compositions containing thecoronavirus 3C-Like protease inhibitor in a mammal by administeringeffective amounts of such coronavirus 3C-Like protease inhibitor.

BACKGROUND OF THE INVENTION

Coronaviruses are family of single-stranded, positive-strand RNA viruseswith viral envelopes, classified within the Nidovirales order. Thecoronavirus family comprises pathogens of many animal species, includinghumans, horses, cattle, pigs, birds, cats and monkeys, and have beenknown for more than 60 years. The isolation of the prototype murinecoronavirus strain JHM, for example, was reported in 1949. Coronavirusesare common viruses that generally cause mild to moderateupper-respiratory tract illnesses in humans, and are named for thecrown-like spikes on their envelope surface. There are four majorsub-groups known as alpha, beta, gamma and delta coronaviruses, with thefirst coronaviruses identified in the mid-1960s. The coronaviruses knownto infect humans include alpha coronaviruses 229E and NL63; and betacoronaviruses OC43, HKU1, SARS-CoV (the coronavirus that causes severeacute respiratory syndrome, or SARS), and MERS-CoV (the coronavirus thatcauses Middle East Respiratory Syndrome, or MERS). People are commonlyinfected with human coronaviruses 229E, NL63, 0C43 and HKU1, andsymptoms usually include mild to moderate upper-respiratory tractillnesses of short duration, such as runny nose, cough, sore throat, andfever. Occasionally human coronaviruses result in lower-respiratorytract illnesses, such as pneumonia, although this is more common inpeople with cardiopulmonary disease or compromised immune systems, or inthe elderly. Transmission of the common human coronaviruses is not fullyunderstood. However, it is likely that human coronaviruses spread froman infected person to others through the air by coughing and sneezing,and through close personal contact, such as touching or shaking hands.These viruses may also spread by touching contaminated objects orsurfaces then touching the mouth, nose, or eyes.

Coronaviruses are enveloped, positive-sense, single-stranded RNAviruses. The genomic RNA of CoVs has a 5′-cap structure and 3′-poly-Atail and contains at least 6 open reading frames (ORFs). The first ORF(ORF 1a/b) directly translates two polyproteins: pp1a and pp1ab. Thesepolyproteins are processed by a 3C-Like protease (3CLpro), also known asthe main protease (Mpro), into 16 non-structural proteins. Thesenon-structural proteins engage in the production of subgenomic RNAs thatencode four structural proteins, namely envelope, membrane, spike, andnucleocapsid proteins, among other accessory proteins. As a result, itis understood that 3C-Like protease has a critical role in thecoronavirus life cycle. 3CLpro is a cysteine protease involved in mostcleavage events within the precursor polyprotein. Active 3CLpro is ahomodimer containing two protomers and features a Cys-His dyad locatedin between domains I and II. 3CLpro is conserved among coronaviruses andseveral common features are shared among the substrates of 3CLpro indifferent coronaviruses. As there is no human homolog of 3CLpro, it isan ideal antiviral target. Although compounds have been reported toinhibit 3CLpro activity, only one has been approved as a coronavirustherapy. (Refer to WO 2004101742 A2, US 2005/0143320 A1, US 2006/0014821A1, US 2009/0137818 A1, WO 2013/049382 A2, WO 2013/166319 A1,WO2018/042343 A1, WO2018/023054 A1, WO2005/113580 A1, WO2006/061714 A1,WO2021/205296 A1, WO2021/206876 A1, WO2021/206877 A1, WO2021/207409 A2,WO2021/176369, WO2021/191827, WO2021/212039, WO 2021/252491, WO2022/020242, WO 2022/020711, WO2022/036018, WO 2022/109360, WO2022/109363, U.S. Pat. No. 11,124,497 B1, U.S. Pat. No. 11,174,231 B1and U.S. Pat. No. 11,351,149 B1).

More effective therapies for coronavirus infections are needed due tothis high unmet clinical need.

SUMMARY OF THE INVENTION

The present invention relates to novel antiviral compounds,pharmaceutical compositions comprising such compounds, as well asmethods to treat or prevent viral (particularly coronavirus) infectionin a subject in need of such therapy with said compounds. Compounds ofthe present invention inhibit the protein(s) encoded by a coronavirus orinterfere with the life cycle of a coronavirus and are also useful asantiviral agents. In addition, the present invention provides processesfor the preparation of said compounds.

In certain embodiments, the present invention provides compoundsrepresented by Formula (I), and pharmaceutically acceptable salts,esters and prodrugs thereof,

wherein:A is selected from:

1) —R₁₁;

2) —OR₁₂; and

3) —NR₁₃R₁₄;

B is an optionally substituted aryl or optionally substitutedheteroaryl;Q₁ is selected from:

1) Hydrogen;

2) Optionally substituted —C₁-C₈ alkyl;

3) Optionally substituted —C₃-C₈ cycloalkyl;

4) Optionally substituted 3- to 8-membered heterocyclic;

5) Optionally substituted aryl;

6) Optionally substituted —R₁₅S(O)₂R₁₆;

7) Optionally substituted —R₁₅C(O)R₁₆;

8) Optionally substituted —R₁₅C(O)₂R₁₆; and

9) Optionally substituted —R₁₅C(O)NR₁₃;

R₁, R₂, and R₃ are each independently selected from:

1) Hydrogen;

2) Optionally substituted —C₁-C₈ alkyl;

3) Optionally substituted —C₂-C₈ alkenyl;

4) Optionally substituted —C₂-C₈ alkynyl;

5) Optionally substituted —C₃-C₈ cycloalkyl;

6) Optionally substituted 3- to 8-membered heterocycloalkyl;

7) Optionally substituted aryl;

8) Optionally substituted arylalkyl;

9) Optionally substituted heteroaryl; and

10) Optionally substituted heteroarylalkyl;

alternatively, R₁ and R₂ are taken together with the carbon atom towhich they are attached to form an optionally substituted 3- to8-membered carbocyclic ring or an optionally substituted 3- to8-membered heterocyclic ring.

R₄ is hydrogen, optionally substituted —C₁-C₄ alkyl, optionallysubstituted C₂-C₄-alkenyl, or optionally substituted —C₃-C₆ cycloalkyl.R₁₁ and R₁₂ are each independently selected from:

1) Optionally substituted —C₁-C₈ alkyl;

2) Optionally substituted —C₂-C₈ alkenyl;

3) Optionally substituted —C₂-C₈ alkynyl;

4) Optionally substituted —C₃-C₈ cycloalkyl;

5) Optionally substituted 3- to 8-membered heterocycloalkyl;

6) Optionally substituted aryl;

7) Optionally substituted arylalkyl;

8) Optionally substituted heteroaryl; and

9) Optionally substituted heteroarylalkyl;

R₁₃ and R₁₄ each independently selected from:

1) Hydrogen;

2) Optionally substituted —C₁-C₈ alkyl;

3) Optionally substituted —C₂-C₈ alkenyl;

4) Optionally substituted —C₂-C₈ alkynyl;

5) Optionally substituted —C₃-C₅ cycloalkyl;

6) Optionally substituted 3- to 8-membered heterocycloalkyl;

7) Optionally substituted aryl;

8) Optionally substituted arylalkyl;

9) Optionally substituted heteroaryl; and

10) Optionally substituted heteroarylalkyl;

alternatively, R₁₃ and R₁₄ are taken together with the nitrogen atom towhich they are attached to form an optionally substituted 3- to8-membered heterocyclic ring.

R₁₅ is absent, or optionally substituted —C₁-C₈ alkyl; andR₁₆ is selected from:

1) Optionally substituted —C₁-C₈ alkyl;

2) Optionally substituted —C₂-C₈ alkenyl;

3) Optionally substituted —C₂-C₈ alkynyl;

4) Optionally substituted —C₃-C₈ cycloalkyl;

5) Optionally substituted 3- to 8-membered heterocycloalkyl;

6) Optionally substituted aryl;

7) Optionally substituted arylalkyl;

8) Optionally substituted heteroaryl; and

9) Optionally substituted heteroarylalkyl.

DETAILED DESCRIPTION OF THE INVENTION

In one embodiment of the present invention is a compound of Formula (I)as described above, or a pharmaceutically acceptable salt thereof.

In one embodiment of the present invention, the compound of Formula (I)is represented by Formula (I-A) or Formula (I-B), or a pharmaceuticallyacceptable salt, ester or prodrug thereof:

wherein A, B, Q₁, R₁, R₂, R₃, and R₄ are as previously defined.

In a preferred embodiment, the compound of Formula (I) has thestereochemistry shown in Formula (I-A).

In certain embodiments of the compounds of Formula (I), R₁ is hydrogen,optionally substituted —C₁-C₆ alkyl; optionally substituted —C₃-C₆cycloalkyl; optionally substituted C₃-C₆ cycloalkyl-C₁-C₂-alkyl;optionally substituted aryl; optionally substituted arylalkyl;optionally substituted heteroarylalkyl.

In certain embodiments of the compounds of Formula (I), R₂ is hydrogen,optionally substituted —C₁-C₄ alkyl; optionally substituted —C₃-C₆cycloalkyl; optionally substituted aryl; optionally substitutedarylalkyl; or optionally substituted heteroarylalkyl.

In certain embodiments of the compounds of Formula (I), R₁ is selectedfrom the following groups:

In certain embodiments of the compounds of Formula (I), R₂ is hydrogen,and R₁ is hydrogen, optionally substituted —C₁-C₆ alkyl; optionallysubstituted —C₃-C₆ cycloalkyl; optionally substituted C₃-C₆cycloalkyl-C₁-C₂-alkyl; optionally substituted aryl; optionallysubstituted arylalkyl; or optionally substituted heteroarylalkyl.

In certain embodiments of the compounds of Formula (I), R₂ is hydrogen,and R₁ is selected from the following groups:

In certain embodiments of the compounds of Formula (I) or Formula (Ia),R₃ is hydrogen or optionally substituted —C₁-C₄ alkyl; and R₄ ishydrogen or optionally substituted —C₁-C₄ alkyl.

In certain embodiments of the compounds of Formula (I), R₃ is hydrogen,-Me, -Et, —Pr, -i-Pr, -allyl, —CF₃, —CD₃ or cyclopropyl.

In certain embodiments of the compounds of Formula (I), R₄ is hydrogen,-Me, -Et, —Pr, -i-Pr, -allyl, —CF₃ or cyclopropyl.

In certain embodiments of the compounds of Formula (I), R₃ is hydrogen,and R₄ is hydrogen.

In certain embodiments of the compounds of Formula (I), R₂ is hydrogen,R₃ is hydrogen or —CH₃, R₄ is hydrogen, and R₁ is hydrogen, optionallysubstituted —C₁-C₆ alkyl; optionally substituted —C₃-C₆ cycloalkyl;optionally substituted C₃-C₆ cycloalkyl-C₁-C₂-alkyl-optionallysubstituted aryl; optionally substituted arylalkyl; or optionallysubstituted heteroarylalkyl.

In certain embodiments of the compounds of Formula (I), R₂ is hydrogen,R₃ is hydrogen or —CH₃, R₄ is hydrogen, and R₁ is selected from thefollowing groups:

In certain embodiments of the compounds of Formula (I), Q₁ is hydrogen.

In certain embodiments of the compounds of Formula (I), A is derivedfrom one of the following by removal of a hydrogen atom and isoptionally substituted:

In certain embodiments of the compounds of Formula (I), A is selectedfrom the following groups, and A is optionally substituted:

preferably the substituents are independently selected from halogen, CN,NH₂, optionally substituted —C₁-C₃ alkoxy, optionally substituted —C₁-C₃alkyl, optionally substituted —C₃-C₆ cycloalkyl, optionally substitutedaryl, and optionally substituted heteroaryl. Preferably the number ofsubstituents is 0 to 3.

In certain embodiments of the compounds of Formula (I), A is selectedfrom the following groups, and A is optionally substituted:

preferably the substituents are independently selected from halogen, CN,NH₂, optionally substituted —C₁-C₃ alkoxy, optionally substituted —C₁-C₃alkyl, optionally substituted —C₃-C₆ cycloalkyl, optionally substitutedaryl, and optionally substituted heteroaryl. Preferably the number ofsubstituents is 0 to 3.

In certain embodiments of the compounds of Formula (I), A is selectedfrom the following groups, and A is optionally substituted:

In certain embodiments of the compounds of Formula (I), B is selectedfrom the following groups, and B is optionally substituted:

In certain embodiments, the compound of Formula (I), is represented byFormula (II), or a pharmaceutically acceptable salt, ester, or prodrugthereof:

wherein A, B, R₁, R₃, R₄, and Q₁ are as previously defined.

In certain embodiments, the compound of Formula (I), is represented byFormula (III), or a pharmaceutically acceptable salt, ester, or prodrugthereof:

wherein A, B, R₁, R₂, R₃, and Q₁ are as previously defined.

In certain embodiments, the compound of Formula (I), is represented byFormula (III-1), or a pharmaceutically acceptable salt, ester, orprodrug thereof:

wherein A, B, R₁, and R₃, are as previously defined.

In certain embodiments, the compound of Formula (I), is represented byFormula (IV), or a pharmaceutically acceptable salt, ester, or prodrugthereof:

wherein A, B, R₁, and Q₁ are as previously defined.

In certain embodiments, the compound of Formula (I), is represented byFormula (V), or a pharmaceutically acceptable salt, ester, or prodrugthereof:

wherein A, B, and R₁ are as previously defined.

In certain embodiments, the compound of Formula (I), is represented byFormula (V-A), or a pharmaceutically acceptable salt, ester, or prodrugthereof:

wherein A, B, and R₁ are as previously defined.

In certain embodiments, the compound of Formula (I) is represented byFormula (VI), or a pharmaceutically acceptable salt, ester, or prodrugthereof:

wherein A, Q₁, R₁, R₂, R₃, and R₄ are as previously defined, each R₉ isindependently selected from:

1) Halogen;

2) —CN;

3) —OR₁₃;

4) —SR₁₃;

5) —NR₁₃R₁₄;

6) —OC(O)NR₁₃R₁₄;

7) Optionally substituted —C₁-C₆ alkyl;

8) Optionally substituted —C₃-C₈ cycloalkyl;

9) Optionally substituted 3- to 8-membered heterocycloalkyl;

10) Optionally substituted aryl; and

11) Optionally substituted heteroaryl;

and n is 0, 1, 2, 3, or 4; preferably, n is 0, 1, or 2.

In certain embodiments, the compound of Formula (I) is represented byFormula (VII), or a pharmaceutically acceptable salt, ester, or prodrugthereof:

wherein A, Q₁, R₁, R₃, R₄, R₉, and n are as previously defined.

In certain embodiments, the compound of Formula (I) is represented byFormula (VIII), or a pharmaceutically acceptable salt, ester, or prodrugthereof:

wherein A, Q₁, R₁, R₂, R₃, R₉, and n are as previously defined.

In certain embodiments, the compound of Formula (I) is represented byFormula (IX), or a pharmaceutically acceptable salt, ester, or prodrugthereof:

wherein A, Q₁, R₁, R₃, R₉, and n are as previously defined.

In certain embodiments, the compound of Formula (I) is represented byFormula (X), or a pharmaceutically acceptable salt, ester, or prodrugthereof:

wherein A, R₁, and R₃ are as previously defined.

In certain embodiments, the compound of Formula (I) is represented byFormula (X-A), or a pharmaceutically acceptable salt, ester, or prodrugthereof:

wherein A, R₁, and R₃ are as previously defined.

In certain embodiments of the compounds of Formula (X), or Formula(X-A), wherein R₃ is hydrogen or —CH₃; R₁ is selected from:

andA is derived from one of the following by removal of a hydrogen atom andis optionally substituted:

In certain embodiments, the compound of Formula (I) is represented byone of Formulae (XI-1)˜(XI-5), or a pharmaceutically acceptable salt,ester, or prodrug thereof:

wherein R₁, R₃, R₄, R₉, and n are as previously defined, each R₁₀ isindependently selected from:

1) Halogen;

2) —CN;

3) —OR₁₃;

4) —SR₁₃;

5) —NR₁₃R₁₄;

6) —OC(O)NR₁₃R₁₄;

7) Optionally substituted —C₁-C₆ alkyl;

8) Optionally substituted —C₃-C₈ cycloalkyl;

9) Optionally substituted 3- to 8-membered heterocycloalkyl;

10) Optionally substituted aryl; and

11) Optionally substituted heteroaryl;

and m is 0, 1, 2, 3, or 4; preferably m is 0, 1 or 2.

In certain embodiments, the compound of Formula (I) is represented byone of Formulae (XII-1) to (XII-5), or a pharmaceutically acceptablesalt, ester, or prodrug thereof:

wherein R₁, R₃, R₄, R₁₀, and m are as previously defined.

In certain embodiments, the compound of Formula (I) is represented byone of Formulae (XII-1A) to (XII-5A), or a pharmaceutically acceptablesalt, ester, or prodrug thereof:

wherein R₁, R₃, R₄, R₁₀, and m are as previously defined.

In certain embodiments, the compound of Formula (I) is represented byone of Formulae (XII-1) to (XII-5), or Formulae (XII-1A) to (XII-5A), ora pharmaceutically acceptable salt, ester, or prodrug thereof, wherein mis 0, 1, 2 or 3; R₁₀ is selected from halogen, CN, NH₂, optionallysubstituted —C₁-C₃ alkoxy, optionally substituted —C₁-C₃ alkyl,optionally substituted —C₃-C₆ cycloalkyl, optionally substituted aryl,and optionally substituted heteroaryl; R₃ is hydrogen or —CH₃, and R₁ isselected from the groups below:

Preferably, R₃ is hydrogen, and R₁ is

It will be appreciated that the description of the present inventionherein should be construed in congruity with the laws and principles ofchemical bonding. In some instances, it may be necessary to remove ahydrogen atom in order to accommodate a substituent at any givenlocation.

It will be yet appreciated that the compounds of the present inventionmay contain one or more asymmetric carbon atoms and may exist inracemic, diastereoisomeric, and optically active forms. It will still beappreciated that certain compounds of the present invention may exist indifferent tautomeric forms. All tautomers are contemplated to be withinthe scope of the present invention.

The compounds of the present invention and any other pharmaceuticallyactive agent(s) may be administered together or separately and, whenadministered separately, administration may occur simultaneously orsequentially, in any order. The amounts of the compounds of the presentinvention and the other pharmaceutically active agent(s) and therelative timings of administration will be selected in order to achievethe desired combined therapeutic effect. The administration incombination of a compound of the present invention and salts, solvates,or other pharmaceutically acceptable derivatives thereof with othertreatment agents may be achieved by concomitant administration in: (1) aunitary pharmaceutical composition including both compounds; or (2)separate pharmaceutical compositions each including one of thecompounds.

In certain embodiments of the combination therapy, the additionaltherapeutic agent is administered at a lower dose and/or dosingfrequency as compared to dose and/or dosing frequency of the additionaltherapeutic agent required to achieve similar results in treating orpreventing coronavirus.

It should be understood that the compounds encompassed by the presentinvention are those that are suitably stable for use as pharmaceuticalagent.

Definitions

Listed below are definitions of various terms used to describe thisinvention. These definitions apply to the terms as they are usedthroughout this specification and claims, unless otherwise limited inspecific instances, either individually or as part of a larger group.

The term “aryl,” as used herein, refers to a mono- or polycycliccarbocyclic ring system comprising at least one aromatic ring. Preferredaryl groups are C₆-C₁₂-aryl groups, including, but not limited to,phenyl, naphthyl, tetrahydronaphthyl, indanyl, and indenyl. A polycyclicaryl is a polycyclic ring system that comprises at least one aromaticring. Polycyclic aryls can comprise fused rings, covalently attachedrings or a combination thereof.

The term “heteroaryl,” as used herein, refers to a mono- or polycyclicaromatic radical having one or more ring atom selected from S, O and N;and the remaining ring atoms are carbon, wherein any N or S containedwithin the ring may be optionally oxidized. In certain embodiments, aheteroaryl group is a 5- to 10-membered heteroaryl, such as a 5- or6-membered monocyclic heteroaryl or an 8- to 10-membered bicyclicheteroaryl. Heteroaryl groups include, but are not limited to,pyridinyl, pyrazinyl, pyrimidinyl, pyrrolyl, pyrazolyl, imidazolyl,thiazolyl, oxazolyl, isooxazolyl, thiadiazolyl, oxadiazolyl, thiophenyl,furanyl, quinolinyl, isoquinolinyl, benzimidazolyl, benzoxazolyl,quinoxalinyl. A polycyclic heteroaryl can comprise fused rings,covalently attached rings or a combination thereof. A heteroaryl groupcan be C-attached or N-attached where possible.

In accordance with the invention, aryl and heteroaryl groups can besubstituted or unsubstituted.

The term “bicyclic aryl” or “bicyclic heteroaryl” refers to a ringsystem consisting of two rings wherein at least one ring is aromatic;and the two rings can be fused or covalently attached.

The term “alkyl” as used herein, refers to saturated, straight- orbranched-chain hydrocarbon radicals. “C₁-C₄ alkyl,” “C₁-C₆ alkyl,”“C₁-C₈ alkyl,” “C₁-C₁₂ alkyl,” “C₂-C₄ alkyl,” and “C₃-C₆ alkyl,” referto alkyl groups containing from 1 to 4, 1 to 6, 1 to 8, 1 to 12, 2 to 4and 3 to 6 carbon atoms respectively. Examples of alkyl groups include,but are not limited to, methyl, ethyl, propyl, isopropyl, n-butyl,sec-butyl, tert-butyl, n-pentyl, neopentyl, n-hexyl, n-heptyl andn-octyl radicals.

The term “alkenyl” as used herein, refers to straight- or branched-chainhydrocarbon radicals having at least one carbon-carbon double bond.“C₂-C₈ alkenyl,” “C₂-C₁₂ alkenyl,” “C₂-C₄ alkenyl,” “C₃-C₄ alkenyl,” and“C₃-C₆ alkenyl,” refer to alkenyl groups containing from 2 to 8, 2 to12, 2 to 4, 3 to 4 or 3 to 6 carbon atoms respectively. Alkenyl groupsinclude, but are not limited to, ethenyl, propenyl, butenyl,2-methyl-2-buten-2-yl, heptenyl, octenyl, and the like.

The term “alkynyl” as used herein, refers to straight- or branched-chainhydrocarbon radicals having at least one carbon-carbon triple bond.“C₂-C₈ alkynyl,” “C₂-C₁₂ alkynyl,” “C₂-C₄ alkynyl,” “C₃-C₄ alkynyl,” and“C₃-C₆ alkynyl,” refer to alkynyl groups containing from 2 to 8, 2 to12, 2 to 4, 3 to 4 or 3 to 6 carbon atoms respectively. Representativealkynyl groups include, but are not limited to, ethynyl, 2-propynyl,2-butynyl, heptynyl, octynyl, and the like.

The term “cycloalkyl”, as used herein, refers to a monocyclic orpolycyclic saturated carbocyclic ring, such as a bi- or tri-cyclicfused, bridged or spiro system. The ring carbon atoms are optionallyoxo-substituted or optionally substituted with an exocyclic olefinicdouble bond. Preferred cycloalkyl groups include C₃-C₁₂ cycloalkyl,C₃-C₆ cycloalkyl, C₃-C₈ cycloalkyl and C₄-C₇ cycloalkyl. Examples ofcycloalkyl include, but are not limited to, cyclopropyl, cyclobutyl,cyclopentyl, cyclohexyl, cyclopentyl, cyclooctyl,4-methylene-cyclohexyl, bicyclo[2.2.1]heptyl, bicyclo[3.1.0]hexyl,spiro[2.5]octyl, 3-methylenebicyclo[3.2.1]octyl, spiro[4.4]nonanyl, andthe like.

The term “cycloalkenyl”, as used herein, refers to monocyclic orpolycyclic carbocyclic ring, such as a bi- or tri-cyclic fused, bridgedor spiro system having at least one carbon-carbon double bond. The ringcarbon atoms are optionally oxo-substituted or optionally substitutedwith an exocyclic olefinic double bond. Preferred cycloalkenyl groupsinclude C₃-C₁₂ cycloalkenyl, C₄-C₁₂-cycloalkenyl, C₃-C₈ cycloalkenyl,C₄-C₈ cycloalkenyl and C₅-C₇ cycloalkenyl groups. Examples ofcycloalkenyl include, but are not limited to, cyclopropenyl,cyclobutenyl, cyclopentenyl, cyclohexenyl, cycloheptenyl, cyclooctenyl,bicyclo[2.2.1]hept-2-enyl, bicyclo[3.1.0]hex-2-enyl,spiro[2.5]oct-4-enyl, spiro[4.4]non-2-enyl,bicyclo[4.2.1]non-3-en-12-yl, and the like.

As used herein, the term “arylalkyl” means a functional group wherein analkylene chain is attached to an aryl group, e.g., —(CH₂)_(n)-phenyl,where n is 1 to 12, preferably 1 to 6 and more preferably 1 or 2. Theterm “substituted arylalkyl” means an arylalkyl functional group inwhich the aryl group is substituted. Similarly, the term“heteroarylalkyl” means a functional group wherein an alkylene chain, isattached to a heteroaryl group, e.g., —(CH₂)_(n)-heteroaryl, where n is1 to 12, preferably 1 to 6 and more preferably 1 or 2. The term“substituted heteroarylalkyl” means a heteroarylalkyl functional groupin which the heteroaryl group is substituted.

As used herein, the term “alkoxy” refers to a radical in which an alkylgroup having the designated number of carbon atoms is connected to therest of the molecule via an oxygen atom. Alkoxy groups includeC₁-C₁₂-alkoxy, C₁-C₈-alkoxy, C₁-C₆-alkoxy, C₁-C₄-alkoxy and C₁-C₃-alkoxygroups. Examples of alkoxy groups includes, but are not limited to,methoxy, ethoxy, n-propoxy, 2-propoxy (isopropoxy) and the higherhomologs and isomers. Preferred alkoxy is C₁-C₃alkoxy.

An “aliphatic” group is a non-aromatic moiety comprised of anycombination of carbon atoms, hydrogen atoms, halogen atoms, oxygen,nitrogen or other atoms, and optionally contains one or more units ofunsaturation, e.g., double and/or triple bonds. Examples of aliphaticgroups are functional groups, such as alkyl, alkenyl, alkynyl, O, OH,NH, NH₂, C(O), S(O)₂, C(O)O, C(O)NH, OC(O)O, OC(O)NH, OC(O)NH₂, S(O)₂NH,S(O)₂NH₂, NHC(O)NH₂, NHC(O)C(O)NH, NHS(O)₂NH, NHS(O)₂NH₂, C(O)NHS(O)₂,C(O)NHS(O)₂NH or C(O)NHS(O)₂NH₂, and the like, groups comprising one ormore functional groups, non-aromatic hydrocarbons (optionallysubstituted), and groups wherein one or more carbons of a non-aromatichydrocarbon (optionally substituted) is replaced by a functional group.Carbon atoms of an aliphatic group can be optionally oxo-substituted. Analiphatic group may be straight chained, branched, cyclic, or acombination thereof and preferably contains between about 1 and about 24carbon atoms, more typically between about 1 and about 12 carbon atoms.In addition to aliphatic hydrocarbon groups, as used herein, aliphaticgroups expressly include, for example, alkoxyalkyls, polyalkoxyalkyls,such as polyalkylene glycols, polyamines, and polyimines, for example.Aliphatic groups may be optionally substituted.

The terms “heterocyclic” and “heterocycloalkyl” can be usedinterchangeably and refer to a non-aromatic ring or a polycyclic ringsystem, such as a bi- or tri-cyclic fused, bridged or spiro system,where (i) each ring system contains at least one heteroatomindependently selected from oxygen, sulfur and nitrogen, (ii) each ringsystem can be saturated or unsaturated (iii) the nitrogen and sulfurheteroatoms may optionally be oxidized, (iv) the nitrogen heteroatom mayoptionally be quaternized, (v) any of the above rings may be fused to anaromatic ring, and (vi) the remaining ring atoms are carbon atoms whichmay be optionally oxo-substituted or optionally substituted withexocyclic olefinic double bond. Representative heterocycloalkyl groupsinclude, but are not limited to, 1,3-dioxolane, pyrrolidinyl,pyrazolinyl, pyrazolidinyl, imidazolinyl, imidazolidinyl, piperidinyl,piperazinyl, oxazolidinyl, isoxazolidinyl, morpholinyl, thiazolidinyl,isothiazolidinyl, quinoxalinyl, pyridazinonyl,2-azabicyclo[2.2.1]-heptyl, 8-azabicyclo[3.2.1]octyl,5-azaspiro[2.5]octyl, 2-oxa-7-azaspiro[4.4]nonanyl, 7-oxooxepan-4-yl,and tetrahydrofuryl. Such heterocyclic or heterocycloalkyl groups may befurther substituted. A heterocycloalkyl or heterocyclic group can beC-attached or N-attached where possible.

It is understood that any alkyl, alkenyl, alkynyl, alicyclic,cycloalkyl, cycloalkenyl, aryl, heteroaryl, heterocyclic, aliphaticmoiety or the like described herein can also be a divalent ormultivalent group when used as a linkage to connect two or more groupsor substituents, which can be at the same or different atom(s). One ofskill in the art can readily determine the valence of any such groupfrom the context in which it occurs.

The term “substituted” refers to substitution by independent replacementof one, two, or three or more of the hydrogen atoms with substituentsincluding, but not limited to, —F, —Cl, —Br, —I, —OH, C₁-C₁₂-alkyl;C₂-C₁₂-alkenyl, C₂-C₁₂-alkynyl, —C₃-C₁₂-cycloalkyl, protected hydroxy,—NO₂, —N₃, —CN, —NH₂, protected amino, oxo, thioxo, —NH—C₁-C₁₂-alkyl,—NH—C₂-C₈-alkenyl, —NH—C₂-C₈-alkynyl, —NH—C₃-C₁₂-cycloalkyl, —NH-aryl,—NH-heteroaryl, —NH-heterocycloalkyl, -dialkylamino, -diarylamino,-diheteroarylamino, —O—C₁-C₁₂-alkyl, —O—C₂-C₈-alkenyl, —O—C₂-C₈-alkynyl,—O—C₃-C₁₂-cycloalkyl, —O-aryl, —O-heteroaryl, —O-heterocycloalkyl,—C(O)—C₁-C₁₂-alkyl, —C(O)—C₂-C₈-alkenyl, —C(O)—C₂-C₈-alkynyl,—C(O)—C₃-C₁₂-cycloalkyl, —C(O)-aryl, —C(O)— heteroaryl,—C(O)-heterocycloalkyl, —CONH₂, —CONH—C₁-C₁₂-alkyl, —CONH—C₂-C₈-alkenyl,—CONH—C₂-C₈-alkynyl, —CONH—C₃-C₁₂-cycloalkyl, —CONH-aryl,—CONH-heteroaryl, —CONH— heterocycloalkyl, —OCO₂—C₁-C₁₂-alkyl,—OCO₂—C₂-C₈-alkenyl, —OCO₂—C₂-C₈-alkynyl, —OCO₂—C₃-C₁₂-cycloalkyl,—OCO₂-aryl, —OCO₂-heteroaryl, —OCO₂-heterocycloalkyl, —CO₂—C₁-C₁₂ alkyl,—CO₂—C₂-C₈ alkenyl, —CO₂—C₂-C₈ alkynyl, —CO₂—C₃-C₁₂-cycloalkyl,—CO₂-aryl, —CO₂-heteroaryl, —CO₂-heterocyloalkyl, —OCONH₂,—OCONH—C₁-C₁₂-alkyl, —OCONH—C₂-C₈-alkenyl, —OCONH—C₂-C₈-alkynyl,—OCONH—C₃-C₁₂-cycloalkyl, —OCONH-aryl, —OCONH-heteroaryl, —OCONH—heterocycloalkyl, —NHC(O)H, —NHC(O)—C₁-C₁₂-alkyl, —NHC(O)—C₂-C₈-alkenyl,—NHC(O)—C₂-C₈-alkynyl, —NHC(O)—C₃-C₁₂-cycloalkyl, —NHC(O)-aryl,—NHC(O)-heteroaryl, —NHC(O)— heterocycloalkyl, —NHCO₂—C₁-C₁₂-alkyl,—NHCO₂—C₂-C₈-alkenyl, —NHCO₂—C₂-C₈-alkynyl, —NHCO₂—C₃-C₁₂-cycloalkyl,—NHCO₂-aryl, —NHCO₂-heteroaryl, —NHCO₂— heterocycloalkyl, —NHC(O)NH₂,—NHC(O)NH—C₁-C₁₂-alkyl, —NHC(O)NH—C₂-C₈-alkenyl,—NHC(O)NH—C₂-C₈-alkynyl, —NHC(O)NH—C₃-C₁₂-cycloalkyl, —NHC(O)NH-aryl,—NHC(O)NH-heteroaryl, —NHC(O)NH-heterocycloalkyl, —NHC(S)NH₂,—NHC(S)NH—C₁-C₁₂-alkyl, —NHC(S)NH—C₂-C₈-alkenyl,—NHC(S)NH—C₂-C₈-alkynyl, —NHC(S)NH—C₃-C₁₂-cycloalkyl, —NHC(S)NH-aryl,—NHC(S)NH-heteroaryl, —NHC(S)NH-heterocycloalkyl, —NHC(NH)NH₂,—NHC(NH)NH—C₁-C₁₂-alkyl, —NHC(NH)NH—C₂-C₈-alkenyl,—NHC(NH)NH—C₂-C₈-alkynyl, —NHC(NH)NH—C₃-C₁₂-cycloalkyl, —NHC(NH)NH-aryl,—NHC(NH)NH-heteroaryl, —NHC(NH)NH-heterocycloalkyl,—NHC(NH)—C₁-C₁₂-alkyl, —NHC(NH)—C₂-C₈-alkenyl, —NHC(NH)—C₂-C₈-alkynyl,—NHC(NH)—C₃-C₁₂-cycloalkyl, —NHC(NH)-aryl, —NHC(NH)-heteroaryl,—NHC(NH)-heterocycloalkyl, —C(NH)NH₂, —C(NH)NH—C₁-C₁₂-alkyl,—C(NH)NH—C₂-C₈-alkenyl, —C(NH)NH—C₂-C₈-alkynyl,—C(NH)NH—C₃-C₁₂-cycloalkyl, —C(NH)NH-aryl, —C(NH)NH-heteroaryl,—C(NH)NH— heterocycloalkyl, —S(O)—C₁-C₁₂-alkyl, —S(O)—C₂-C₈-alkenyl,—S(O)—C₂-C₈-alkynyl, —S(O)—C₃-C₁₂-cycloalkyl, —S(O)-aryl,—S(O)-heteroaryl, —S(O)-heterocycloalkyl, —SO₂NH₂, —SO₂NH—C₁-C₁₂-alkyl,—SO₂NH—C₂-C₈-alkenyl, —SO₂NH—C₂-C₈-alkynyl, —SO₂—C₁-C₁₂-alkyl,—SO₂—C₂-C₈-alkenyl, —SO₂—C₂-C₈-alkynyl, —SO₂—C₃-C₁₂-cycloalkyl,—SO₂-aryl, —SO₂-heteroaryl, —SO₂-heterocycloalkyl,—SO₂NH—C₃-C₁₂-cycloalkyl, —SO₂NH-aryl, —SO₂NH-heteroaryl,—SO₂NH-heterocycloalkyl, —NHSO₂—C₁-C₁₂-alkyl, —NHSO₂—C₂-C₈-alkenyl,—NHSO₂—C₂-C₈-alkynyl, —NHSO₂—C₃-C₁₂-cycloalkyl, —NHSO₂-aryl,—NHSO₂-heteroaryl, —NHSO₂-heterocycloalkyl, —CH₂NH₂, —CH₂SO₂CH₃, -aryl,-arylalkyl, -heteroaryl, -heteroarylalkyl, -heterocycloalkyl,—C₃-C₁₂-cycloalkyl, polyalkoxyalkyl, polyalkoxy, -methoxymethoxy,-methoxyethoxy, —SH, —S—C₁-C₁₂-alkyl, —S—C₂-C₈-alkenyl,—S—C₂-C₈-alkynyl, —S—C₃-C₁₂-cycloalkyl, —S-aryl, —S-heteroaryl, —S—heterocycloalkyl, or methylthio-methyl. In certain embodiments, thesubstituents are independently selected from halo, preferably C₁ and F;C₁-C₄-alkyl, preferably methyl and ethyl; halo-C₁-C₄-alkyl, such asfluoromethyl, difluoromethyl, and trifluoromethyl; C₂-C₄-alkenyl;halo-C₂-C₄-alkenyl; C₃-C₆-cycloalkyl, such as cyclopropyl; C₁-C₄-alkoxy,such as methoxy and ethoxy; halo-C₁-C₄-alkoxy, such as fluoromethoxy,difluoromethoxy, and trifluoromethoxy; —CN; —OH; NH₂; C₁-C₄-alkylamino;di(C₁-C₄-alkyl)amino; and NO₂. It is understood that an aryl,heteroaryl, alkyl, alkenyl, alkynyl, cycloalkyl, or heterocycloalkyl ina substituent can be further substituted. In certain embodiments, asubstituent in a substituted moiety is additionally optionallysubstituted with one or more groups, each group being independentlyselected from C₁-C₄-alkyl; —CF₃, —OCH₃, —OCF₃, —F, —Cl, —Br, —I, —OH,—NO₂, —CN, and —NH₂. Preferably, a substituted alkyl group issubstituted with one or more halogen atoms, more preferably one or morefluorine or chlorine atoms.

The term “halo” or halogen” alone or as part of another substituent, asused herein, refers to a fluorine, chlorine, bromine, or iodine atom.

The term “optionally substituted”, as used herein, means that thereferenced group may be substituted or unsubstituted. In one embodiment,the referenced group is optionally substituted with zero substituents,i.e., the referenced group is unsubstituted. In another embodiment, thereferenced group is optionally substituted with one or more additionalgroup(s) individually and independently selected from groups describedherein.

The term “hydrogen” includes hydrogen and deuterium. In addition, therecitation of an element includes all isotopes of that element so longas the resulting compound is pharmaceutically acceptable. In certainembodiments, the isotopes of an element are present at a particularposition according to their natural abundance. In other embodiments, oneor more isotopes of an element at a particular position are enrichedbeyond their natural abundance.

The term “hydroxy activating group,” as used herein, refers to a labilechemical moiety which is known in the art to activate a hydroxyl groupso that it will depart during synthetic procedures such as in asubstitution or an elimination reaction. Examples of hydroxyl activatinggroup include, but not limited to, mesylate, tosylate, triflate,p-nitrobenzoate, phosphonate and the like.

The term “activated hydroxyl,” as used herein, refers to a hydroxy groupactivated with a hydroxyl activating group, as defined above, including,but not limited to mesylate, tosylate, triflate, p-nitrobenzoate,phosphonate groups.

The term “hydroxy protecting group,” as used herein, refers to a labilechemical moiety which is known in the art to protect a hydroxyl groupagainst undesired reactions during synthetic procedures. After saidsynthetic procedure(s) the hydroxy protecting group as described hereinmay be selectively removed. Hydroxy protecting groups as known in theart are described generally in P. G. M. Wuts, Greene's Protective Groupsin Organic Synthesis, 5th edition, John Wiley & Sons, Hoboken, N.J.(2014). Examples of hydroxyl protecting groups include, but not limitedto, benzyloxycarbonyl, 4-methoxybenzyloxycarbonyl, tert-butoxycarbonyl,isopropoxycarbonyl, diphenylmethoxycarbonyl,2,2,2-trichloroethoxycarbonyl, allyloxycarbonyl, acetyl, formyl,chloroacetyl, trifluoroacetyl, methoxyacetyl, phenoxyacetyl, benzoyl,methyl, t-butyl, 2,2,2-trichloroethyl, 2-trimethylsilyl ethyl, allyl,benzyl, triphenyl-methyl (trityl), methoxymethyl, methylthiomethyl,benzyloxymethyl, 2-(trimethylsilyl)-ethoxymethyl, methanesulfonyl,trimethylsilyl, triisopropylsilyl, and the like.

The term “protected hydroxy,” as used herein, refers to a hydroxy groupprotected with a hydroxy protecting group, as defined above, includingbut not limited to, benzoyl, acetyl, trimethylsilyl, triethylsilyl,methoxymethyl groups, for example.

The term “hydroxy prodrug group,” as used herein, refers to a promoietygroup which is known in the art to change the physicochemical, and hencethe biological properties of a parent drug in a transient manner bycovering or masking the hydroxy group. After said syntheticprocedure(s), the hydroxy prodrug group as described herein must becapable of reverting back to hydroxy group in vivo. Hydroxy prodruggroups as known in the art are described generally in Kenneth B. Sloan,Prodrugs, Topical and Ocular Drug Delivery, (Drugs and thePharmaceutical Sciences; Volume 53), Marcel Dekker, Inc., New York(1992).

The term “amino protecting group,” as used herein, refers to a labilechemical moiety which is known in the art to protect an amino groupagainst undesired reactions during synthetic procedures. After saidsynthetic procedure(s) the amino protecting group as described hereinmay be selectively removed. Amino protecting groups as known in the artare described generally in P. G. M. Wuts, Greene's Protective Groups inOrganic Synthesis, 5th edition, John Wiley & Sons, Hoboken, N.J. (2014).Examples of amino protecting groups include, but are not limited to,methoxycarbonyl, t-butoxycarbonyl, 12-fluorenyl-methoxycarbonyl,benzyloxycarbonyl, and the like.

The term “protected amino,” as used herein, refers to an amino groupprotected with an amino protecting group as defined above.

The term “leaving group” means a functional group or atom which can bedisplaced by another functional group or atom in a substitutionreaction, such as a nucleophilic substitution reaction. By way ofexample, representative leaving groups include chloro, bromo and iodogroups; sulfonic ester groups, such as mesylate, tosylate, brosylate,nosylate and the like; and acyloxy groups, such as acetoxy,trifluoroacetoxy and the like.

The term “aprotic solvent,” as used herein, refers to a solvent that isrelatively inert to proton activity, i.e., not acting as a proton-donor.Examples include, but are not limited to, hydrocarbons, such as hexaneand toluene, for example, halogenated hydrocarbons, such as, forexample, methylene chloride, ethylene chloride, chloroform, and thelike, heterocyclic compounds, such as, for example, tetrahydrofuran andN-methylpyrrolidinone, and ethers such as diethyl ether,bis-methoxymethyl ether. Such compounds are well known to those skilledin the art, and it will be obvious to those skilled in the art thatindividual solvents or mixtures thereof may be preferred for specificcompounds and reaction conditions, depending upon such factors as thesolubility of reagents, reactivity of reagents and preferred temperatureranges, for example. Further discussions of aprotic solvents may befound in organic chemistry textbooks or in specialized monographs, forexample: Organic Solvents Physical Properties and Methods ofPurification, 4th ed., edited by John A. Riddick et al., Vol. II, in theTechniques of Chemistry Series, John Wiley & Sons, N Y, 1986.

The term “protic solvent,” as used herein, refers to a solvent thattends to provide protons, such as an alcohol, for example, methanol,ethanol, propanol, isopropanol, butanol, t-butanol, and the like. Suchsolvents are well known to those skilled in the art, and it will beobvious to those skilled in the art that individual solvents or mixturesthereof may be preferred for specific compounds and reaction conditions,depending upon such factors as the solubility of reagents, reactivity ofreagents and preferred temperature ranges, for example. Furtherdiscussions of protogenic solvents may be found in organic chemistrytextbooks or in specialized monographs, for example: Organic SolventsPhysical Properties and Methods of Purification, 4th ed., edited by JohnA. Riddick et al., Vol. II, in the Techniques of Chemistry Series, JohnWiley & Sons, N Y, 1986.

Combinations of substituents and variables envisioned by this inventionare only those that result in the formation of stable compounds. Theterm “stable,” as used herein, refers to compounds which possessstability sufficient to allow manufacture and which maintains theintegrity of the compound for a sufficient period of time to be usefulfor the purposes detailed herein (e.g., therapeutic or prophylacticadministration to a subject).

The synthesized compounds can be separated from a reaction mixture andfurther purified by a method such as column chromatography, highpressure liquid chromatography, or recrystallization. As can beappreciated by the skilled artisan, further methods of synthesizing thecompounds of the Formula herein will be evident to those of ordinaryskill in the art. Additionally, the various synthetic steps may beperformed in an alternate sequence or order to give the desiredcompounds. Synthetic chemistry transformations and protecting groupmethodologies (protection and deprotection) useful in synthesizing thecompounds described herein are known in the art and include, forexample, those such as described in R. Larock, Comprehensive OrganicTransformations, 2^(nd) Ed. Wiley-VCH (1999); P. G. M. Wuts, Greene'sProtective Groups in Organic Synthesis, 5th edition, John Wiley & Sons,Hoboken, N.J. (2014); L. Fieser and M. Fieser, Fieser and Fieser'sReagents for Organic Synthesis, John Wiley and Sons (1994); and L.Paquette, ed., Encyclopedia of Reagents for Organic Synthesis, JohnWiley and Sons (1995), and subsequent editions thereof.

The term “subject,” as used herein, refers to an animal. Preferably, theanimal is a mammal. More preferably, the mammal is a human. A subjectalso refers to, for example, a dog, cat, horse, cow, pig, guinea pig,fish, bird and the like.

The compounds of this invention may be modified by appending appropriatefunctionalities to enhance selective biological properties. Suchmodifications are known in the art and may include those which increasebiological penetration into a given biological system (e.g., blood,lymphatic system, central nervous system), increase oral availability,increase solubility to allow administration by injection, altermetabolism and alter rate of excretion.

The compounds described herein contain one or more asymmetric centersand thus give rise to enantiomers, diastereomers, and otherstereoisomeric forms that may be defined, in terms of absolutestereochemistry, as (R)- or (S)-, or as (D)- or (L)- for amino acids.The present invention is meant to include all such possible isomers, aswell as their racemic and optically pure forms. Optical isomers may beprepared from their respective optically active precursors by theprocedures described above, or by resolving the racemic mixtures. Theresolution can be carried out in the presence of a resolving agent, bychromatography or by repeated crystallization or by some combination ofthese techniques which are known to those skilled in the art. Furtherdetails regarding resolutions can be found in Jacques, et al.,Enantiomers, Racemates, and Resolutions (John Wiley & Sons, 1981). Whenthe compounds described herein contain olefinic double bonds, otherunsaturation, or other centers of geometric asymmetry, and unlessspecified otherwise, it is intended that the compounds include both Eand Z geometric isomers or cis- and trans-isomers. Likewise, alltautomeric forms are also intended to be included. Tautomers may be incyclic or acyclic. The configuration of any carbon-carbon double bondappearing herein is selected for convenience only and is not intended todesignate a particular configuration unless the text so states; thus acarbon-carbon double bond or carbon-heteroatom double bond depictedarbitrarily herein as trans may be cis, trans, or a mixture of the twoin any proportion.

Certain compounds of the present invention may also exist in differentstable conformational forms which may be separable. Torsional asymmetrydue to restricted rotation about an asymmetric single bond, for examplebecause of steric hindrance or ring strain, may permit separation ofdifferent conformers. The present invention includes each conformationalisomer of these compounds and mixtures thereof.

As used herein, the term “pharmaceutically acceptable salt,” refers tothose salts which are, within the scope of sound medical judgment,suitable for use in contact with the tissues of humans and lower animalswithout undue toxicity, irritation, allergic response and the like, andare commensurate with a reasonable benefit/risk ratio. Pharmaceuticallyacceptable salts are well known in the art. For example, S. M. Berge, etal. describes pharmaceutically acceptable salts in detail in J.Pharmaceutical Sciences, 66: 2-19 (1977). The salts can be prepared insitu during the final isolation and purification of the compounds of theinvention, or separately by reacting the free base function with asuitable organic acid. Examples of pharmaceutically acceptable saltsinclude, but are not limited to, nontoxic acid addition salts are saltsof an amino group formed with inorganic acids such as hydrochloric acid,hydrobromic acid, phosphoric acid, sulfuric acid and perchloric acid orwith organic acids such as acetic acid, maleic acid, tartaric acid,citric acid, succinic acid or malonic acid or by using other methodsused in the art such as ion exchange. Other pharmaceutically acceptablesalts include, but are not limited to, adipate, alginate, ascorbate,aspartate, benzenesulfonate, benzoate, bisulfate, borate, butyrate,camphorate, camphorsulfonate, citrate, cyclopentane-propionate,digluconate, dodecylsulfate, ethanesulfonate, formate, fumarate,glucoheptonate, glycerophosphate, gluconate, hemisulfate, heptanoate,hexanoate, hydroiodide, 2-hydroxy-ethanesulfonate, lactobionate,lactate, laurate, lauryl sulfate, malate, maleate, malonate,methanesulfonate, 2-naphthalenesulfonate, nicotinate, nitrate, oleate,oxalate, palmitate, pamoate, pectinate, persulfate, 3-phenylpropionate,phosphate, picrate, pivalate, propionate, stearate, succinate, sulfate,tartrate, thiocyanate, p-toluenesulfonate, undecanoate, valerate salts,and the like. Representative alkali or alkaline earth metal saltsinclude sodium, lithium, potassium, calcium, magnesium, and the like.Further pharmaceutically acceptable salts include, when appropriate,nontoxic ammonium, quaternary ammonium, and amine cations formed usingcounterions such as halide, hydroxide, carboxylate, sulfate, phosphate,nitrate, alkyl having from 1 to 6 carbon atoms, sulfonate and arylsulfonate.

As used herein, the term “pharmaceutically acceptable ester” refers toesters which hydrolyze in vivo and include those that break down readilyin the human body to leave the parent compound or a salt thereof.Suitable ester groups include, for example, those derived frompharmaceutically acceptable aliphatic carboxylic acids, particularlyalkanoic, alkenoic, cycloalkanoic and alkanedioic acids, in which eachalkyl or alkenyl moiety advantageously has not more than 6 carbon atoms.Examples of particular esters include, but are not limited to, formates,acetates, propionates, butyrates, acrylates and ethylsuccinates.

Pharmaceutical Compositions

The pharmaceutical compositions of the present invention comprise atherapeutically effective amount of a compound of the present inventionformulated together with one or more pharmaceutically acceptablecarriers or excipients.

As used herein, the term “pharmaceutically acceptable carrier orexcipient” means a non-toxic, inert solid, semi-solid or liquid filler,diluent, encapsulating material or formulation auxiliary of any type.Some examples of materials which can serve as pharmaceuticallyacceptable carriers are sugars such as lactose, glucose and sucrose;starches such as corn starch and potato starch; cellulose and itsderivatives such as sodium carboxymethyl cellulose, ethyl cellulose andcellulose acetate; powdered tragacanth; malt; gelatin; talc; excipientssuch as cocoa butter and suppository waxes; oils such as peanut oil,cottonseed oil, safflower oil, sesame oil, olive oil, corn oil andsoybean oil; glycols such as propylene glycol; esters such as ethyloleate and ethyl laurate; agar; buffering agents such as magnesiumhydroxide and aluminum hydroxide; alginic acid; pyrogen-free water;isotonic saline; Ringer's solution; ethyl alcohol, and phosphate buffersolutions, as well as other non-toxic compatible lubricants such assodium lauryl sulfate and magnesium stearate, as well as coloringagents, releasing agents, coating agents, sweetening, flavoring andperfuming agents, preservatives and antioxidants can also be present inthe composition, according to the judgment of the formulator.

The pharmaceutical compositions of this invention may be administeredorally, parenterally, by inhalation spray, topically, rectally, nasally,buccally, vaginally or via an implanted reservoir, preferably by oraladministration or administration by injection. The pharmaceuticalcompositions of this invention may contain any conventional non-toxicpharmaceutically-acceptable carriers, adjuvants or vehicles. In somecases, the pH of the formulation may be adjusted with pharmaceuticallyacceptable acids, bases or buffers to enhance the stability of theformulated compound or its delivery form. The term parenteral as usedherein includes subcutaneous, intracutaneous, intravenous,intramuscular, intraarticular, intra-arterial, intrasynovial,intrasternal, intrathecal, intralesional and intracranial injection orinfusion techniques.

Liquid dosage forms for oral administration include pharmaceuticallyacceptable emulsions, microemulsions, solutions, suspensions, syrups andelixirs. In addition to the active compounds, the liquid dosage formsmay contain inert diluents commonly used in the art such as, forexample, water or other solvents, solubilizing agents and emulsifierssuch as ethyl alcohol, isopropyl alcohol, ethyl carbonate, ethylacetate, benzyl alcohol, benzyl benzoate, propylene glycol, 1,3-butyleneglycol, dimethylformamide, oils (in particular, cottonseed, groundnut,corn, germ, olive, castor, and sesame oils), glycerol,tetrahydrofurfuryl alcohol, polyethylene glycols and fatty acid estersof sorbitan, and mixtures thereof. Besides inert diluents, the oralcompositions can also include adjuvants such as wetting agents,emulsifying and suspending agents, sweetening, flavoring, and perfumingagents.

Injectable preparations, for example, sterile injectable aqueous oroleaginous suspensions, may be formulated according to the known artusing suitable dispersing or wetting agents and suspending agents. Thesterile injectable preparation may also be a sterile injectablesolution, suspension or emulsion in a nontoxic parenterally acceptablediluent or solvent, for example, as a solution in 1,3-butanediol. Amongthe acceptable vehicles and solvents that may be employed are water,Ringer's solution, U.S.P. and isotonic sodium chloride solution. Inaddition, sterile, fixed oils are conventionally employed as a solventor suspending medium. For this purpose, any bland fixed oil can beemployed including synthetic mono- or diglycerides. In addition, fattyacids such as oleic acid are used in the preparation of injectable.

The injectable formulations can be sterilized, for example, byfiltration through a bacterial-retaining filter, or by incorporatingsterilizing agents in the form of sterile solid compositions which canbe dissolved or dispersed in sterile water or other sterile injectablemedium prior to use.

In order to prolong the effect of a drug, it is often desirable to slowthe absorption of the drug from subcutaneous or intramuscular injection.This may be accomplished by the use of a liquid suspension ofcrystalline or amorphous material with poor water solubility. The rateof absorption of the drug then depends upon its rate of dissolution,which, in turn, may depend upon crystal size and crystalline form.Alternatively, delayed absorption of a parenterally administered drugform is accomplished by dissolving or suspending the drug in an oilvehicle. Injectable depot forms are made by forming microencapsulematrices of the drug in biodegradable polymers such aspolylactide-polyglycolide. Depending upon the ratio of drug to polymerand the nature of the particular polymer employed, the rate of drugrelease can be controlled. Examples of other biodegradable polymersinclude poly(orthoesters) and poly(anhydrides). Depot injectableformulations are also prepared by entrapping the drug in liposomes ormicroemulsions that are compatible with body tissues.

Compositions for rectal or vaginal administration are preferablysuppositories which can be prepared by mixing the compounds of thisinvention with suitable non-irritating excipients or carriers such ascocoa butter, polyethylene glycol or a suppository wax which are solidat ambient temperature but liquid at body temperature and therefore meltin the rectum or vaginal cavity and release the active compound.

Solid dosage forms for oral administration include capsules, tablets,pills, powders, and granules. In such solid dosage forms, the activecompound is mixed with at least one inert, pharmaceutically acceptableexcipient or carrier such as sodium citrate or dicalcium phosphateand/or: a) fillers or extenders such as starches, lactose, sucrose,glucose, mannitol, and silicic acid, b) binders such as, for example,carboxymethylcellulose, alginates, gelatin, polyvinylpyrrolidinone,sucrose, and acacia, c) humectants such as glycerol, d) disintegratingagents such as agar-agar, calcium carbonate, potato or tapioca starch,alginic acid, certain silicates, and sodium carbonate, e) solutionretarding agents such as paraffin, f) absorption accelerators such asquaternary ammonium compounds, g) wetting agents such as, for example,cetyl alcohol and glycerol monostearate, h) absorbents such as kaolinand bentonite clay, and i) lubricants such as talc, calcium stearate,magnesium stearate, solid polyethylene glycols, sodium lauryl sulfate,and mixtures thereof. In the case of capsules, tablets and pills, thedosage form may also comprise buffering agents.

Solid compositions of a similar type may also be employed as fillers insoft and hard-filled gelatin capsules using such excipients as lactoseor milk sugar as well as high molecular weight polyethylene glycols andthe like.

The solid dosage forms of tablets, dragees, capsules, pills, andgranules can be prepared with coatings and shells such as entericcoatings and other coatings well known in the pharmaceutical formulatingart. They may optionally contain opacifying agents and can also be of acomposition that they release the active ingredient(s) only, orpreferentially, in a certain part of the intestinal tract, optionally,in a delayed manner. Examples of embedding compositions that can be usedinclude polymeric substances and waxes.

Dosage forms for topical or transdermal administration of a compound ofthis invention include ointments, pastes, creams, lotions, gels,powders, solutions, sprays, inhalants or patches. The active componentis admixed under sterile conditions with a pharmaceutically acceptablecarrier and any needed preservatives or buffers as may be required.Ophthalmic formulations, ear drops, eye ointments, powders and solutionsare also contemplated as being within the scope of this invention.

The ointments, pastes, creams and gels may contain, in addition to anactive compound of this invention, excipients such as animal andvegetable fats, oils, waxes, paraffins, starch, tragacanth, cellulosederivatives, polyethylene glycols, silicones, bentonites, silicic acid,talc and zinc oxide, or mixtures thereof.

Powders and sprays can contain, in addition to the compounds of thisinvention, excipients such as lactose, talc, silicic acid, aluminumhydroxide, calcium silicates and polyamide powder, or mixtures of thesesubstances. Sprays can additionally contain customary propellants suchas chlorofluorohydrocarbons.

Transdermal patches have the added advantage of providing controlleddelivery of a compound to the body. Such dosage forms can be made bydissolving or dispensing the compound in the proper medium. Absorptionenhancers can also be used to increase the flux of the compound acrossthe skin. The rate can be controlled by either providing a ratecontrolling membrane or by dispersing the compound in a polymer matrixor gel.

For pulmonary delivery, a therapeutic composition of the invention isformulated and administered to the patient in solid or liquidparticulate form by direct administration e.g., inhalation into therespiratory system. Solid or liquid particulate forms of the activecompound prepared for practicing the present invention include particlesof respirable size: that is, particles of a size sufficiently small topass through the mouth and larynx upon inhalation and into the bronchiand alveoli of the lungs. Delivery of aerosolized therapeutics,particularly aerosolized antibiotics, is known in the art (see, forexample U.S. Pat. No. 5,767,068 to Van Devanter et al., U.S. Pat. No.5,508,269 to Smith et al., and WO 98/43650 by Montgomery, all of whichare incorporated herein by reference).

Antiviral Activity

In certain embodiments, the present invention provides a method oftreating or preventing a viral infection in a subject in need thereof,comprising administering to the subject a therapeutically effectiveamount of a compound of Formula (I) or a pharmaceutically acceptablesalt thereof. The viral infection is preferably a coronavirus infection.In certain embodiments, the coronavirus is SARS-CoV-1, SARS-CoV-2, orMERS-CoV. Preferably the coronavirus is SARS-CoV-2.

A viral inhibitory amount or dose of the compounds of the presentinvention may range from about 0.01 mg/Kg to about 500 mg/Kg,alternatively from about 1 to about 50 mg/Kg. Inhibitory amounts ordoses will also vary depending on route of administration, as well asthe possibility of co-usage with other agents.

According to the methods of treatment of the present invention, viralinfections are treated or prevented in a patient such as a human oranother animal by administering to the patient a therapeuticallyeffective amount of a compound of the invention, in such amounts and forsuch time as is necessary to achieve the desired result.

By a “therapeutically effective amount” of a compound of the inventionis meant an amount of the compound which confers a therapeutic effect onthe treated subject, at a reasonable benefit/risk ratio applicable toany medical treatment. The therapeutic effect may be objective (i.e.,measurable by some test or marker) or subjective (i.e., subject gives anindication of or feels an effect). A therapeutically effective amount ofthe compound described above may range, for example, from about 0.1mg/Kg to about 500 mg/Kg, preferably from about 1 to about 50 mg/Kg.Effective doses will also vary depending on route of administration, aswell as the possibility of co-usage with other agents. It will beunderstood, however, that the total daily usage of the compounds andcompositions of the present invention will be decided by the attendingphysician within the scope of sound medical judgment. The specifictherapeutically effective dose level for any particular patient willdepend upon a variety of factors including the disorder being treatedand the severity of the disorder; the activity of the specific compoundemployed; the specific composition employed; the age, body weight,general health, sex and diet of the patient; the time of administration,route of administration, and rate of excretion of the specific compoundemployed; the duration of the treatment; drugs used in combination orcontemporaneously with the specific compound employed; and like factorswell known in the medical arts.

The total daily dose of the compounds of this invention administered toa human or other animal in single or in divided doses can be in amounts,for example, from 0.01 to 50 mg/kg body weight or more usually from 0.1to 25 mg/kg body weight. Single dose compositions may contain suchamounts or submultiples thereof to make up the daily dose. In general,treatment regimens according to the present invention compriseadministration to a patient in need of such treatment from about 10 mgto about 1000 mg of the compound(s) of this invention per day in singleor multiple doses.

The compounds of the present invention described herein can, forexample, be administered by injection, intravenously, intra-arterial,subdermally, intraperitoneally, intramuscularly, or subcutaneously; ororally, buccally, nasally, transmucosally, topically, in an ophthalmicpreparation, or by inhalation, with a dosage ranging from about 0.1 toabout 500 mg/kg of body weight, alternatively dosages between 1 mg and1000 mg/dose, every 4 to 120 hours, or according to the requirements ofthe particular drug. The methods herein contemplate administration of aneffective amount of compound or compound composition to achieve thedesired or stated effect. Typically, the pharmaceutical compositions ofthis invention will be administered from about 1 to about 6 times perday or alternatively, as a continuous infusion. Such administration canbe used as a chronic or acute therapy. The amount of active ingredientthat may be combined with pharmaceutically excipients or carriers toproduce a single dosage form will vary depending upon the host treatedand the particular mode of administration. A typical preparation willcontain from about 5% to about 95% active compound (w/w). Alternatively,such preparations may contain from about 20% to about 80% activecompound.

Lower or higher doses than those recited above may be required. Specificdosage and treatment regimens for any particular patient will dependupon a variety of factors, including the activity of the specificcompound employed, the age, body weight, general health status, sex,diet, time of administration, rate of excretion, drug combination, theseverity and course of the disease, condition or symptoms, the patient'sdisposition to the disease, condition or symptoms, and the judgment ofthe treating physician.

Upon improvement of a patient's condition, a maintenance dose of acompound, composition or combination of this invention may beadministered, if necessary. Subsequently, the dosage or frequency ofadministration, or both, may be reduced, as a function of the symptoms,to a level at which the improved condition is retained when the symptomshave been alleviated to the desired level. Patients may, however,require intermittent treatment on a long-term basis upon any recurrenceof disease symptoms.

Combination and Alternation Therapy

The compounds of the present invention may be used in combination withone or more antiviral therapeutic agents or anti-inflammatory agentsuseful in the prevention or treatment of viral diseases or associatedpathophysiology. Thus, the compounds of the present invention and theirsalts, solvates, or other pharmaceutically acceptable derivativesthereof, may be employed alone or in combination with other antiviral oranti-inflammatory therapeutic agents. The compounds herein andpharmaceutically acceptable salts thereof may be used in combinationwith one or more other agents which may be useful in the prevention ortreatment of respiratory disease, inflammatory disease, autoimmunedisease, for example; anti-histamines, corticosteroids, (e.g.,fluticasone propionate, fluticasone furoate, beclomethasonedipropionate, budesonide, ciclesonide, mometasone furoate,triamcinolone, flunisolide), NSAIDs, leukotriene modulators (e.g.,montelukast, zafirlukast.pranlukast), tryptase inhibitors, IKK2inhibitors, p38 inhibitors, Syk inhibitors, protease inhibitors such aselastase inhibitors, integrin antagonists (e.g., beta-2 integrinantagonists), adenosine A2a agonists, mediator release inhibitors suchas sodium chromoglycate, 5-lipoxygenase inhibitors (zyflo), DP1antagonists, DP2 antagonists, PI3K delta inhibitors, ITK inhibitors, LP(Iysophosphatidic) inhibitors or FLAP (5-lipoxygenase activatingprotein) inhibitors (e.g., sodium3-(3-(tert-butylthio)-1-(4-(6-ethoxypyridin-3-yl)benzyl)-5-((5-ethylpyridin-2-yl)methoxy)-1H-indol-2-yl)-2,2-dimethylpropanoate),bronchodilators (e.g., muscarinic antagonists, beta-2 agonists),methotrexate, and similar agents; monoclonal antibody therapy such asanti-lgE, anti-TNF, anti-IL-5, anti-IL-6, anti-IL-12, anti-IL-1 andsimilar agents; cytokine receptor therapies e.g. etanercept and similaragents; antigen non-specific immunotherapies (e.g. interferon or othercytokines/chemokines, chemokine receptor modulators such as CCR3, CCR4or CXCR2 antagonists, other cytokine/chemokine agonists or antagonists,TLR agonists and similar agents), suitable anti-infective agentsincluding antibiotic agents, antifungal agents, antheimintic agents,antimalarial agents, antiprotozoal agents, antitubercuiosis agents, andantiviral agents, including those listed athttps://www.drugs.com/drug-class/anti-infectives.html. In general,combination therapy is typically preferred over alternation therapybecause it induces multiple simultaneous stresses on the virus.

When the compositions of this invention comprise a combination of acompound of the Formula described herein and one or more additionaltherapeutic or prophylactic agents, both the compound and the additionalagent should be present at dosage levels of between about 1 to 100%, andmore preferably between about 5 to 95% of the dosage normallyadministered in a monotherapy regimen. The additional agents may beadministered separately, as part of a multiple dose regimen, from thecompounds of this invention. Alternatively, those agents may be part ofa single dosage form, combined with a compound of this invention in asingle composition.

The “additional therapeutic or prophylactic agents” include but are notlimited to, immune therapies (e.g. interferon), therapeutic vaccines,antifibrotic agents, anti-inflammatory agents such as corticosteroids orNSAIDs, bronchodilators such as beta-2 adrenergic agonists and xanthines(e.g. theophylline), mucolytic agents, anti-muscarinics,anti-leukotrienes, inhibitors of cell adhesion (e.g. ICAM antagonists),anti-oxidants (e.g. N-acetylcysteine), cytokine agonists, cytokineantagonists, lung surfactants and/or antimicrobial and anti-viral agents(e.g. ribavirin and amantidine). The compositions according to theinvention may also be used in combination with gene replacement therapy.

Although the invention has been described with respect to variouspreferred embodiments, it is not intended to be limited thereto, butrather those skilled in the art will recognize that variations andmodifications may be made therein which are within the spirit of theinvention and the scope of the appended claims.

Abbreviations

Abbreviations which may be used in the descriptions of the scheme andthe examples that follow are: Ac for acetyl; AcOH for acetic acid; Boc₂Ofor di-tert-butyl-dicarbonate; Boc for t-butoxycarbonyl; Bz for benzoyl;Bn for benzyl; t-BuOK for potassium tert-butoxide; Brine for sodiumchloride solution in water; CDI for carbonyldiimidazole; DCM or CH₂Cl₂for dichloromethane; CH₃ for methyl; CH₃CN for acetonitrile; Cs₂CO₃ forcesium carbonate; CuCl for copper (I) chloride; CuI for copper (I)iodide; dba for dibenzylidene acetone; DBU for1,8-diazabicyclo[5.4.0]-undec-7-ene; DEAD for diethylazodicarboxylate;DIAD for diisopropyl azodicarboxylate; DIPEA or (i-Pr)₂EtN forN,N,-diisopropylethyl amine; DMP or Dess-Martin periodinane for1,1,2-tris(acetyloxy)-1,2-dihydro-1,2-benziodoxol-3-(1H)-one; DMAP for4-dimethylamino-pyridine; DME for 1,2-dimethoxyethane; DMF forN,N-dimethylformamide; DMSO for dimethyl sulfoxide; EtOAc for ethylacetate; EtOH for ethanol; Et₂O for diethyl ether; HATU forO-(7-azabenzotriazol-2-yl)-N,N,N′,N′,-tetramethyluroniumHexafluoro-phosphate; HCl for hydrogen chloride; K₂CO₃ for potassiumcarbonate; n-BuLi for n-butyl lithium; DDQ for2,3-dichloro-5,6-dicyano-1,4-benzoquinone; LDA for lithiumdiisopropylamide; LiTMP for lithium 2,2,6,6-tetramethyl-piperidinate;MeOH for methanol; Mg for magnesium; MOM for methoxymethyl; Ms for mesylor —SO₂—CH₃; NaHMDS for sodium bis(trimethylsilyl)amide; NaCl for sodiumchloride; NaH for sodium hydride; NaHCO₃ for sodium bicarbonate orsodium hydrogen carbonate; Na₂CO₃ sodium carbonate; NaOH for sodiumhydroxide; Na₂SO₄ for sodium sulfate; NaHSO₃ for sodium bisulfite orsodium hydrogen sulfite; Na₂S₂O₃ for sodium thiosulfate; NH₂NH₂ forhydrazine; NH₄C₁ for ammonium chloride; Ni for nickel; OH for hydroxyl;OsO₄ for osmium tetroxide; OTf for triflate; PPA for polyphosphoricacid; PTSA for p-toluenesulfonic acid; PPTS for pyridiniump-toluenesulfonate; TBAF for tetrabutylammonium fluoride; TEA or Et₃Nfor triethylamine; TES for triethylsilyl; TESCl for triethylsilylchloride; TESOTf for triethylsilyl trifluoromethanesulfonate; TFA fortrifluoroacetic acid; THE for tetrahydrofuran; TMEDA forN,N,N′,N′-tetramethylethylene-diamine; TPP or PPh₃ fortriphenyl-phosphine; Tos or Ts for tosyl or —SO₂—C₆H₄CH₃; Ts₂O fortolylsulfonic anhydride or tosyl-anhydride; TsOH for p-tolylsulfonicacid; Pd for palladium; Ph for phenyl; Pd₂(dba)₃ fortris(diben-zylideneacetone) dipalladium (0); Pd(PPh₃)₄ fortetrakis(triphenylphosphine)-palladium (0); PdCl₂(PPh₃)₂ fortrans-dichlorobis-(triphenylphosphine)palladium (II); Pt for platinum;Rh for rhodium; rt for room temperature; Ru for ruthenium; TBS fortert-butyl dimethylsilyl; TMS for trimethylsilyl; and TMSCl fortrimethylsilyl chloride.

Synthetic Methods

Scheme 1 illustrates a general method to prepare the compound of formula(Ia) from the amino ester compound (X-1), wherein B is as previouslydefined and PG₁ is C₁-C₄ alkyl or Bn. In Step 1, treatment of amine(X-1) with formaldehyde affords the cyclized amine (X-2), which isconverted in Step 2 to (X-3) using appropriate protecting group PG₂(e.g. Boc). In Step 3, treatment of (X-3) with NBS in solventscontaining AcOH at low temperature provides the rearranged spiro prolinederivative (X-4). Examples of this sequence of transformation has beenreported in literature (Pellegrini C. et al. “Synthesis of the OxindoleAlkaloid (−)-Horsfiline” Tetrahedron Asymmetry, 1994, vol. 5, No. 10, pp1979-1992; Efremov, I. V. et al. “Discovery and Optimization of a NovelSpiropyrrolidine Inhibitor of β-Secretase (BACE1) through Fragment-BasedDrug Design” Journal of Medicinal Chemistry, 2012, 55, 9069-9088). InStep 4, the ester compound of formula (X-4), wherein B, PG₁ and PG₂ arepreviously defined, is reduced to the alcohol compound (X-5) employingreducing reagents such as, but not limited to, LiBH₄, NaBH₄, or DIBAL-H.In Step 5, the alcohol compound of formula (X-5) is oxidized to thealdehyde compound of formula (X-6) using agents such as, but not limitedto, Dess-Martin periodinane, IBX, or pyridine-SO₃. In Step 6, thealdehyde compound of formula (X-6) is reacted with a phosphonate estersuch as a compound of formula (X-7), to produce the alkyne compound offormula (X-8). In Step 7, the protecting group of the compound offormula (X-8) is removed under acidic, basic, or reductive conditions toproduce amine compound of formula (X-9). In Step 8, an amide bond isformed between the compound of formula (X-9) and an acid compound suchas a compound of formula (X-10) using a reagent such as, but not limitedto, HATU or DMAP, upon which, followed by a deprotection step underacidic, basic, or reductive conditions, will produce a compound offormula (X-11). In Step 9, an acidic compound of formula (X-12) isreacted with the amine of the compound of formula (X-11) in an amidebond forming reaction using a reagent such as, but not limited to, HATUor DMAP to produce the compound of formula (X-13).

EXAMPLES

The compounds and processes of the present invention will be betterunderstood in connection with the following examples, which are intendedas an illustration only and not limiting of the scope of the invention.Starting materials were either available from a commercial vendor orproduced by methods well known to those skilled in the art.

General Conditions:

Mass spectra were run on LC-MS systems using electrospray ionization.These were Agilent 1290 Infinity II systems with an Agilent 6120Quadrupole detector. Spectra were obtained using a ZORBAX EclipseXDB-C18 column (4.6×30 mm, 1.8 micron). Spectra were obtained at 298Kusing a mobile phase of 0.1% formic acid in water (A) and 0.1% formicacid in acetonitrile (B). Spectra were obtained with the followingsolvent gradient: 5% (B) from 0-1.5 min, 5-95% (B) from 1.5-4.5 min, and95% (B) from 4.5-6 min. The solvent flowrate was 1.2 mL/min. Compoundswere detected at 210 nm and 254 nm wavelengths. [M+H]⁺ refers tomono-isotopic molecular weights.

NMR spectra were run on a Bruker 400 MHz spectrometer. Spectra weremeasured at 298K and referenced using the solvent peak. Chemical shiftsfor ¹H NMR are reported in parts per million (ppm).

Compounds were purified via reverse-phase high-performance liquidchromatography (RPHPLC) using a Gilson GX-281 automated liquid handlingsystem. Compounds were purified on a Phenomenex Kinetex EVO C18 column(250×21.2 mm, 5 micron), unless otherwise specified. Compounds werepurified at 298K using a mobile phase of water (A) and acetonitrile (B)using gradient elution between 0% and 100% (B), unless otherwisespecified. The solvent flowrate was 20 mL/min and compounds weredetected at 254 nm wavelength.

Alternatively, compounds were purified via normal-phase liquidchromatography (NPLC) using a Teledyne ISCO Combiflash purificationsystem. Compounds were purified on a REDISEP silica gel cartridge.Compounds were purified at 298K and detected at 254 nm wavelength.

Ex. 1: Synthesis ofN—((S)-1-((3R,5′S)-5′-ethynyl-2-oxospiro[indoline-3,3′-pyrrolidin]-1′-yl)-4-fluoro-4-methyl-1-oxopentan-2-yl)-5-(methylsulfonyl)-1H-indole-2-carboxamide

Step 1

methyl (S)-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indole-3-carboxylatehydrochloride (500 mg, 1.875 mmol) was dissolved in CH₂Cl₂ (10 ml).Triethylamine (523 μl, 3.75 mmol) and a 2.0 M solution of di-tert-butyldicarbonate in DCM (1031 μl, 2.062 mmol) was added. The mixture wasstirred at rt for 3 h, quenched with sat. NaHCO₃, and extracted withDCM. The organic layer was washed with brine, dried over MgSO₄, andconcentrated in vacuo. Purification of the residue on silica gel with0-30% EtOAc/cyclohexane provided compound 1-2 (578 mg, 1.749 mmol, 93%yield).

Step 2

Compound 1-2 (578 mg) was dissolved in THE (15 ml), AcOH (10 ml), andwater (10 ml). The solution was cooled to −15° C. A solution of NBS (328mg, 1.843 mmol) in THE (5 mL) was added dropwise. The mixture was slowlywarmed to 5° C. over 1 h. The reaction was quenched with Na₂SO₃ and sat.NaHCO₃, and extracted with DCM (2×). The organic layer was washed withbrine, dried with MgSO₄, and concentrated in vacuo. Purification of theresidue on silica gel with 0-50% EtOAc/cyclohexane provided compound 1-3(328 mg, 0.947 mmol, 53.9% yield).

Step 3

To a solution of compound 1-3 (2.5 g, 7.22 mmol) in THE (24.06 mL) wasadded drowpise a solution of 2M LiBH₄ in THE (10.83 mL, 21.65 mmol). Themixture was stirred at rt for 2 hrs and the majority of THE was removedin vacuo. The reaction was quenched carefully with 1N HCl to pH=5-6 (˜22mL) and extracted with EtOAc (3×40 mL). The combined organic layers werewashed with sat NaHCO₃, brine, dried and concentrated. Purification ofthe residue on silica gel with 0-50% EtOAc/Cyclohexane provided compound1-4 (1.54 g, 67% yield).

Step 4

In a 250 mL round-bottomed flask equipped with a stir bar, compound 1-4(2.50 g, 7.85 mmol, 1.0 equiv) was dissolved in methylene chloride (52mL, 0.15M) under a nitrogen atmosphere. The resulting solution wascooled using an ice and water bath. Dess-Martin periodinane (5.00 g,11.8 mmol, 1.5 equiv) was then added in a single portion. The resultingmixture was allowed to warm to room temperature slowly and was stirredfor 16 h. Upon completion, as judged by LCMS analysis of the reactionmixture, the reaction was filtered through a pad of celite usingmethylene chloride to rinse. Following concentration of the filtrate,the residue was purified directly by silica gel column chromatography(gradient elution, 0 to 100% ethyl acetate/cyclohexane) to affordcompound 1-5 (2.31 g, 7.31 mmol, 93% yield).

Step 5

In a 500 mL round-bottomed flask equipped with a stir bar, compound 1-5(2.21 g, 6.99 mmol, 1.0 equiv) was dissolved in methanol (116 mL, 0.6M)at room temperature under a nitrogen atmosphere. The resulting solutionwas cooled using an ice and water bath, and dimethyl(1-diazo-2-oxopropyl)phosphonate (19.5 mL, 8.38 mmol, 10 wt % inacetonitrile, 1.2 equiv) was added, followed by potassium carbonate(1.93 g, 14.0 mmol, 2.0 equiv). The resulting mixture was allowed towarm to room temperature slowly and was stirred for 16 h. Uponcompletion, as judged by LCMS analysis of the reaction mixture, thesolvent was removed under vacuum, and the residue was partitionedbetween ethyl acetate (125 mL) and water (75 mL). The aqueous phase wasextracted with ethyl acetate (50 mL), and the combined organic layerswere dried over magnesium sulfate. After concentration, the cruderesidue was purified by silica gel column chromatography (gradientelution, 0 to 50% ethyl acetate/cyclohexane) to afford compound 1-6(2.02 g, 6.99 mmol, 93% yield).

Step 6

To a 250 mL round-bottomed flask containing compound 1-6 (2.02 g, 6.48mmol, 1.0 equiv) under a nitrogen atmosphere was charged 4M HCl indioxane (32 mL, 20 equiv) at room temperature. After stirring for 2 h,LCMS analysis of the reaction mixture indicated complete consumption ofthe starting material, and the reaction mixture was concentrated undervacuum to afford compound 1-7 (1.61 g, 6.48 mmol) which was useddirectly in the next step without purification.

Step 7

In a 250 mL round-bottomed flask equipped with a stir bar, compound 1-7(1.61 g, 6.48 mmol, 1.0 equiv) and(S)-2-((tert-butoxycarbonyl)amino)-4-fluoro-4-methylpentanoic acid (1.62g, 6.48 mmol, 1.0 equiv) were combined in a mixed solvent system ofmethylene chloride (20.7 mL) and N,N-dimethylformamide (5.2 mL) under anitrogen atmosphere. The resulting mixture was cooled in an ice andwater bath, and N-methylmorpholine (2.28 mL, 20.7 mmol, 3.2 equiv) wasadded, followed by HATU (2.46 g, 6.48 mmol, 1.0 equiv). The mixture wasallowed to warm to room temperature. After 16 h, LCMS analysis indicatedcomplete consumption of the starting material, and the reaction mixturewas diluted with methylene chloride (125 mL). The organic phase waswashed once with 1.2M HCl (40 mL) and once with saturated aqueous sodiumchloride (40 mL) and then dried over magnesium sulfate. Uponconcentration, the crude residue was purified by reversed-phase HPLC(MeCN/water, 0.1% formic acid) affording compound 1-8 (1.29 g, 2.91mmol, 45% yield).

Step 8

In a 40 mL vial equipped with a stir bar, compound 1-8 (356 mg, 0.80mmol, 1.0 equiv) was treated with 4M HCl in dioxane (4.0 mL, 20 equiv)under an air atmosphere. After stirring for 2 h in the capped vial, LCMSanalysis indicated full consumption of the starting material. Thesolvent was subsequently removed under vacuum to afford compound 1-9(305 mg, 0.80 mmol) which was used in the next step withoutpurification.

Step 9

In a 4 mL vial equipped with a stir bar, compound 1-9 (35.0 mg, 0.09mmol, 1.0 equiv) and 5-(methylsulfonyl)-1H-indole-2-carboxylic acid(22.0 mg, 0.09 mmol, 1.0 equiv) were combined in a mixed solvent systemof methylene chloride (0.5 mL) and N,N-dimethylformamide (0.1 mL). Theresulting solution was cooled in an ice and water bath andN-methylmorpholine (32 μL, 0.30 mmol, 3.2 equiv) was added, followed byHATU (35.0 mg, 0.09 mmol, 1.0 equiv). The vial was capped under an airatmosphere, and the reaction mixture was allowed to slowly warm to roomtemperature. After 19 h, LCMS analysis of the reaction mixture indicatedcomplete consumption of the starting material. The reaction was quenchedwith formic acid (100 μL) and concentrated. Purification of the cruderesidue by reversed-phase HPLC (MeCN/water, 0.1% formic acid) affordedEx. 1 (29.9 mg, 0.05 mmol, 57%). ESI MS m/z=563.1 [M−H]⁻.

Ex. 2: Synthesis of4-chloro-N—((S)-1-((3R,5′S)-5′-ethynyl-2-oxospiro[indoline-3,3′-pyrrolidin]-1′-yl)-4-fluoro-4-methyl-1-oxopentan-2-yl)-1H-indole-2-carboxamide

The title compound was prepared according to the procedure for Ex. 1,except that 4-chloro-1H-indole-2-carboxylic acid was used in place of5-(methylsulfonyl)-1H-indole-2-carboxylic acid in Step 9. ¹HNMR(acetone-d6, 400 MHz, PPM): δ 10.90 (s, 1H), 9.72 (s, 1H), 8.26 (d,J=8.8 Hz, 1H), 7.49-7.52 (m, 1H), 7.36-7.37 (m, 1H), 7.22-7.26 (m, 1H),7.15-7.17 (m, 1H), 7.04-7.08 (m, 1H), 7.0 (d, J=7.5 Hz, 1H), 6.93 (d,J=7.7, 1H), 6.74 (td, J=7.6, 1.1 Hz, 1H), 5.05-5.20 (m, 2H), 4.35 (d,J=10.5, 1H), 3.98 (d, J=10.5 Hz, 1H), 2.93 (d, J=2.1 Hz, 1H), 2.53-2.64(m, 2H), 2.21-2.42 (m, 2H), 1.50 (s, 3H), 1.45 (s, 3H); ESI MS m/z=519.0[M−H]⁻.

Ex. 3: Synthesis of5-chloro-N—((S)-1-((3R,5′S)-5′-ethynyl-2-oxospiro[indoline-3,3′-pyrrolidin]-1′-yl)-4-fluoro-4-methyl-1-oxopentan-2-yl)-1H-indole-2-carboxamide

The title compound was prepared according to the procedure for Ex. 1,except that 5-chloro-1H-indole-2-carboxylic acid was used in place of5-(methylsulfonyl)-1H-indole-2-carboxylic acid in Step 9. ¹HNMR(acetone-d6, 400 MHz, PPM): δ 10.73 (s, 1H), 9.68 (s, 1H), 8.04 (d,J=8.7 Hz, 1H), 7.70 (d, J=2.0 Hz, 1H), 7.56 (d, J=8.7 Hz, 1H), 7.20-7.28(m, 2H), 7.07 (td, J=7.7, 1.2 Hz, 1H), 6.94-6.99 (m, 2H), 6.74 (td,J=7.5, 1.1 Hz, 1H), 5.16-5.03 (m, 2H), 4.34 (d, J=10.4 Hz, 1H), 3.95 (d,J=10.4 Hz, 1H), 2.92 (d, J=2.1 Hz, 1H), 2.53-2.62 (m, 2H), 2.17-2.38 (m,2H), 1.49 (s, 3H), 1.43 (s, 3H); ESI MS m/z=519.1 [M−H]⁻.

Ex. 4: Synthesis of6-chloro-N—((S)-1-((3R,5′S)-5′-ethynyl-2-oxospiro[indoline-3,3′-pyrrolidin]-1′-yl)-4-fluoro-4-methyl-1-oxopentan-2-yl)-1H-indole-2-carboxamide

The title compound was prepared according to the procedure for Ex. 1,except that 6-chloro-1H-indole-2-carboxylic acid was used in place of5-(methylsulfonyl)-1H-indole-2-carboxylic acid in Step 9. ¹HNMR(acetone-d6, 400 MHz, PPM): δ 10.72 (s, 1H), 9.68 (s, 1H), 8.00 (d,J=8.6 Hz, 1H), 7.68 (d, J=8.5 Hz, 1H), 7.58-7.59 (m, 1H), 7.27-7.29 (m,1H), 7.12 (dd, J=8.6, 1.9 Hz, 1H), 7.07 (td, J=7.7, 1.3 Hz, 1H),6.94-6.98 (m, 2H), 6.73 (td, J=7.5, 1.1 Hz, 1H), 5.01-5.17 (m, 2H), 4.34(d, J=10.4 Hz, 1H), 3.94 (d, J=10.4 Hz, 1H), 2.91 (d, J=2.1 Hz, 1H),2.52-2.61 (m, 2H), 2.15-2.38 (m, 2H), 1.49 (s, 3H), 1.43 (s, 3H); ESI MSm/z=519.2 [M−H]⁻.

Ex. 5: Synthesis of7-chloro-N—((S)-1-((3R,5′S)-5′-ethynyl-2-oxospiro[indoline-3,3′-pyrrolidin]-1′-yl)-4-fluoro-4-methyl-1-oxopentan-2-yl)-1H-indole-2-carboxamide

The title compound was prepared according to the procedure for Ex. 1,except that 7-chloro-1H-indole-2-carboxylic acid was used in place of5-(methylsulfonyl)-1H-indole-2-carboxylic acid in Step 9. ¹HNMR(acetone-d6, 400 MHz, PPM): δ 10.29 (s, 1H), 9.69 (s, 1H), 8.04 (d,J=8.7 Hz, 1H), 7.66 (d, J=8.1 Hz, 1H), 7.33-7.35 (m, 1H), 7.30-7.31 (m,1H), 7.12-7.16 (m, 1H), 7.06 (td, J=7.7, 1.3 Hz, 1H), 6.95-6.99 (m, 2H),6.74 (td, J=7.5, 1.1 Hz, 1H), 5.17-5.05 (m, 2H), 4.34 (d, J=10.4 Hz,1H), 3.95 (d, J=10.4 Hz, 1H), 2.92 (d, J=2.1 Hz, 1H), 2.53-2.62 (m, 2H),2.14-2.40 (m, 2H), 1.49 (s, 3H), 1.44 (s, 3H); ESI MS m/z=519.1 [M−H]⁻.

Ex. 6: Synthesis of4,6-dichloro-N—((S)-1-((3R,5′S)-5′-ethynyl-2-oxospiro[indoline-3,3′-pyrrolidin]-1′-yl)-4-fluoro-4-methyl-1-oxopentan-2-yl)-1H-indole-2-carboxamide

The title compound was prepared according to the procedure for Ex. 1,except that 4,6-dichloro-1H-indole-2-carboxylic acid was used in placeof 5-(methylsulfonyl)-1H-indole-2-carboxylic acid in Step 9. ¹HNMR(acetone-d6, 400 MHz, PPM): δ 10.98 (s, 1H), 9.69 (s, 1H), 8.32 (d,J=8.6 Hz, 1H), 7.53 (m, 1H), 7.36-7.37 (m, 1H), 7.21 (d, J=1.6 Hz, 1H),7.07 (td, J=7.7, 1.2 Hz, 1H), 7.03-6.91 (m, 2H), 6.74 (td, J=7.6, 1.1Hz, 1H), 5.18-5.05 (m, 2H), 4.33 (d, J=10.5 Hz, 1H), 3.97 (d, J=10.5 Hz,1H), 2.93 (d, J=2.1 Hz, 1H), 2.54-2.63 (m, 2H), 2.21-2.40 (m, 2H), 1.50(s, 3H), 1.44 (s, 3H); ESI MS m/z=553.0 [M−H]⁻.

Ex. 7: Synthesis of6,7-dichloro-N—((S)-1-((3R,5′S)-5′-ethynyl-2-oxospiro[indoline-3,3′-pyrrolidin]-1′-yl)-4-fluoro-4-methyl-1-oxopentan-2-yl)-1H-indole-2-carboxamide

The title compound was prepared according to the procedure for Ex. 1,except that 6,7-dichloro-1H-indole-2-carboxylic acid was used in placeof 5-(methylsulfonyl)-1H-indole-2-carboxylic acid in Step 9. ESI MSm/z=555.4 [M+H]+.

Ex. 8: Synthesis ofN—((S)-1-((3R,5′S)-5′-ethynyl-2-oxospiro[indoline-3,3′-pyrrolidin]-1′-yl)-4-fluoro-4-methyl-1-oxopentan-2-yl)-7-fluoro-1H-indole-2-carboxamide

The title compound was prepared according to the procedure for Ex. 1,except that 7-fluoro-1H-indole-2-carboxylic acid was used in place of5-(methylsulfonyl)-1H-indole-2-carboxylic acid in Step 9. ¹HNMR(acetone-d6, 400 MHz, PPM): δ 10.82 (s, 1H), 9.67 (s, 1H), 7.97 (d,J=8.6 Hz, 1H), 7.50 (d, J=7.8 Hz, 1H), 7.31 (dd, J=3.2, 2.2 Hz, 1H),6.94-7.11 (m, 5H), 6.77 (td, J=7.5, 1.1 Hz, 1H), 5.20-5.02 (m, 2H), 4.32(d, J=10.5 Hz, 1H), 3.95 (d, J=10.4 Hz, 1H), 2.91 (d, J=2.1 Hz, 1H),2.52-2.62 (m, 2H), 2.15-2.39 (m, 2H), 1.49 (s, 3H), 1.44 (s, 3H); ESI MSm/z=505.2 [M+H]+.

Ex. 9: Synthesis ofN—((S)-1-((3R,5′S)-5′-ethynyl-2-oxospiro[indoline-3,3′-pyrrolidin]-1′-yl)-4-fluoro-4-methyl-1-oxopentan-2-yl)-6-fluoro-1H-indole-2-carboxamide

The title compound was prepared according to the procedure for Ex. 1,except that 6-fluoro-1H-indole-2-carboxylic acid was used in place of5-(methylsulfonyl)-1H-indole-2-carboxylic acid in Step 9. ESI MSm/z=503.2 [M−H]⁻.

Ex. 10: Synthesis ofN—((S)-1-((3R,5′S)-5′-ethynyl-2-oxospiro[indoline-3,3′-pyrrolidin]-1′-yl)-4-fluoro-4-methyl-1-oxopentan-2-yl)-4,6-difluoro-1H-indole-2-carboxamide

The title compound was prepared according to the procedure for Ex. 1,except that 4,6-difluoro-1H-indole-2-carboxylic acid was used in placeof 5-(methylsulfonyl)-1H-indole-2-carboxylic acid in Step 9. ¹HNMR(acetone-d6, 400 MHz, PPM): δ 10.92 (s, 1H), 9.68 (s, 1H), 8.09 (d,J=8.7 Hz, 1H), 7.35 (m, 1H), 7.12 (dd, J=9.4, 1.6 Hz, 1H), 7.07 (td,J=7.7, 1.2 Hz, 1H), 6.94-6.99 (m, 2H), 6.68-6.82 (m, 2H), 5.05-5.14 (m,2H), 4.34 (d, J=10.4 Hz, 1H), 3.95 (d, J=10.4 Hz, 1H), 2.92 (d, J=2.1Hz, 1H), 2.53-2.62 (m, 2H), 2.16-2.39 (m, 2H), 1.49 (s, 3H), 1.43 (s,3H); ESI MS m/z=521.1 [M−H]⁻.

Ex. 11: Synthesis ofN—((S)-1-((3R,5′S)-5′-ethynyl-2-oxospiro[indoline-3,3′-pyrrolidin]-1′-yl)-4-fluoro-4-methyl-1-oxopentan-2-yl)-4,7-difluoro-1H-indole-2-carboxamide

The title compound was prepared according to the procedure for Ex. 1,except that 4,7-difluoro-1H-indole-2-carboxylic acid was used in placeof 5-(methylsulfonyl)-1H-indole-2-carboxylic acid in Step 9. ESI MSm/z=521.2 [M−H]⁻.

Ex. 12: Synthesis ofN—((S)-1-((3R,5′S)-5′-ethynyl-2-oxospiro[indoline-3,3′-pyrrolidin]-1′-yl)-4-fluoro-4-methyl-1-oxopentan-2-yl)-5,6,7-trifluoro-1H-indole-2-carboxamide

The title compound was prepared according to the procedure for Ex. 1,except that 5,6,7-trifluoro-1H-indole-2-carboxylic acid was used inplace of 5-(methylsulfonyl)-1H-indole-2-carboxylic acid in Step 9. ESIMS m/z=539.3 [M−H]⁻.

Ex. 13: Synthesis ofN—((S)-1-((3R,5′S)-5′-ethynyl-2-oxospiro[indoline-3,3′-pyrrolidin]-1′-yl)-4-fluoro-4-methyl-1-oxopentan-2-yl)-7-(trifluoromethyl)-1H-indole-2-carboxamide

The title compound was prepared according to the procedure for Ex. 1,except that 7-(trifluoromethyl)-1H-indole-2-carboxylic acid was used inplace of 5-(methylsulfonyl)-1H-indole-2-carboxylic acid in Step 9. ¹HNMR(acetone-d6, 400 MHz, PPM): δ 9.97 (s, 1H), 9.75 (s, 1H), 8.34 (d, J=8.5Hz, 1H), 7.99 (d, J=8.2 Hz, 1H), 7.63-7.65 (m, 1H), 7.37 (d, J=2.1 Hz,1H), 7.29-7.34 (m, 1H), 6.96-7.07 (m, 3H), 6.75 (td, J=7.5, 1.1 Hz, 1H),5.04-5.23 (m, 2H), 4.38 (d, J=10.4 Hz, 1H), 3.98 (d, J=10.5 Hz, 1H),2.95 (d, J=2.1 Hz, 1H), 2.55-2.65 (m, 2H), 2.19-2.41 (m, 2H), 1.50 (s,3H), 1.44 (s, 3H); ESI MS m/z=553.3 [M−H]⁻.

Ex. 14: Synthesis ofN—((S)-1-((3R,5′S)-5′-ethynyl-2-oxospiro[indoline-3,3′-pyrrolidin]-1′-yl)-4-fluoro-4-methyl-1-oxopentan-2-yl)-5-(trifluoromethyl)-1H-indole-2-carboxamide

The title compound was prepared according to the procedure for Ex. 1,except that 5-(trifluoromethyl)-1H-indole-2-carboxylic acid was used inplace of 5-(methylsulfonyl)-1H-indole-2-carboxylic acid in Step 9. ESIMS m/z=553.2 [M−H]⁻.

Ex 15. Synthesis of7-cyano-N—((S)-1-((3R,5′S)-5′-ethynyl-2-oxospiro[indoline-3,3′-pyrrolidin]-1′-yl)-4-fluoro-4-methyl-1-oxopentan-2-yl)-1H-indole-2-carboxamide

The title compound was prepared according to the procedure for Ex. 1,except that 7-cyano-1H-indole-2-carboxylic acid was used in place of5-(methylsulfonyl)-1H-indole-2-carboxylic acid in Step 9. ESI MSm/z=510.0 [M−H]⁻.

Ex. 16: Synthesis ofN—((S)-1-((3R,5′S)-5′-ethynyl-2-oxospiro[indoline-3,3′-pyrrolidin]-1′-yl)-4-fluoro-4-methyl-1-oxopentan-2-yl)-1H-pyrrolo[2,3-b]pyridine-2-carboxamide

The title compound was prepared according to the procedure for Ex. 1,except that 1H-pyrrolo[2,3-b]pyridine-2-carboxylic acid was used inplace of 5-(methylsulfonyl)-1H-indole-2-carboxylic acid in Step 9. ¹HNMR(acetone-d6, 400 MHz, PPM): δ 11.14 (br s, 1H), 9.66 (s, 1H), 8.43 (dd,J=4.7, 1.6 Hz, 1H), 8.14 (dd, J=7.9, 1.7 Hz, 1H), 8.03 (d, J=8.6 Hz,1H), 7.26 (s, 1H), 7.19 (dd, J=7.9, 4.7 Hz, 1H), 6.99-7.10 (m, 2H),6.89-6.96 (m, 1H), 6.78 (td, J=7.5, 1.1 Hz, 1H), 5.02-5.22 (m, 2H), 4.36(d, J=10.4 Hz, 1H), 3.96 (d, J=10.5 Hz, 1H), 2.92 (d, J=2.1 Hz, 1H),2.53-2.62 (m, 2H), 2.16-2.40 (m, 2H), 1.50 (s, 3H), 1.45 (s, 3H); ESI MSm/z=488.3 [M+H]+.

Ex. 17: Synthesis ofN—((S)-1-((3R,5′S)-5′-ethynyl-2-oxospiro[indoline-3,3′-pyrrolidin]-1′-yl)-4-fluoro-4-methyl-1-oxopentan-2-yl)-7-fluorobenzofuran-2-carboxamide

The title compound was prepared according to the procedure for Ex. 1,except that 7-fluorobenzofuran-2-carboxylic acid was used in place of5-(methylsulfonyl)-1H-indole-2-carboxylic acid in Step 9. ¹HNMR(acetone-d6, 400 MHz, PPM): δ 9.68 (s, 1H), 8.23 (d, J=8.5 Hz, 1H),7.71-7.55 (m, 1H), 7.48 (d, J=2.9 Hz, 1H), 7.43-7.29 (m, 2H), 7.01-7.07(m, 2H), 6.94 (d, J=7.7 Hz, 1H), 6.80 (td, J=7.6, 1.1 Hz, 1H), 5.06-5.15(m, 2H), 4.28 (d, J=10.5 Hz, 1H), 3.95 (d, J=10.5 Hz, 1H), 2.92 (d,J=2.1 Hz, 1H), 2.58 (d, J=8.7 Hz, 2H), 2.22-2.44 (m, 2H), 1.51 (s, 3H),1.45 (s, 3H); ESI MS m/z=506.2 [M+H]+.

Ex. 18:N—((S)-1-((3R,5′S)-5′-ethynyl-2-oxospiro[indoline-3,3′-pyrrolidin]-1′-yl)-4-fluoro-4-methyl-1-oxopentan-2-yl)-5-fluorobenzofuran-2-carboxamide

The title compound was prepared according to the procedure for Ex. 1,except that 5-fluorobenzofuran-2-carboxylic acid was used in place of5-(methylsulfonyl)-1H-indole-2-carboxylic acid in Step 9. ¹HNMR(acetone-d6, 400 MHz, PPM): δ 9.68 (s, 1H), 8.05 (d, J=8.5 Hz, 1H),7.65-7.68 (m, 1H), 7.51-7.51 (m, 1H), 7.41 (d, J=0.9 Hz, 1H), 7.32 (td,J=9.2, 2.7 Hz, 1H), 7.08 (td, J=7.7, 1.2 Hz, 1H), 6.95-7.02 (m, 2H),6.80 (td, J=7.6, 1.1 Hz, 1H), 5.06-5.13 (m, 2H), 4.28 (d, J=10.5 Hz,1H), 3.95 (d, J=10.5 Hz, 1H), 2.92 (d, J=2.1 Hz, 1H), 2.58 (d, J=8.8 Hz,2H), 2.23-2.43 (m, 2H), 1.50 (s, 3H), 1.45 (s, 3H); ESI MS m/z=506.2[M+H]+.

Ex. 19: Synthesis ofN—((S)-1-((3R,5′S)-5′-ethynyl-2-oxospiro[indoline-3,3′-pyrrolidin]-1′-yl)-4-fluoro-4-methyl-1-oxopentan-2-yl)-8-fluoroquinoline-6-carboxamide

The title compound was prepared according to the procedure for Ex. 1,except that 8-fluoroquinoline-6-carboxylic acid was used in place of5-(methylsulfonyl)-1H-indole-2-carboxylic acid in Step 9. ¹HNMR(acetone-d6, 400 MHz, PPM): δ 9.71 (s, 1H), 9.07 (dd, J=4.2, 1.7 Hz,1H), 8.50 (dt, J=8.4, 1.6 Hz, 1H), 8.22-8.29 (m, 2H), 7.78 (dd, J=11.5,1.8 Hz, 1H), 7.73 (dd, J=8.4, 4.2 Hz, 1H), 7.10 (td, J=7.7, 1.2 Hz, 1H),6.94-7.03 (m, 2H), 6.81 (td, J=7.6, 1.1 Hz, 1H), 5.07-5.20 (m, 2H), 4.41(d, J=10.4 Hz, 1H), 3.97 (d, J=10.5 Hz, 1H), 2.93 (d, J=2.1 Hz, 1H),2.55-2.63 (m, 2H), 2.23-2.43 (m, 2H), 1.51 (d, J=2.8 Hz, 3H), 1.46 (d,J=2.8 Hz, 3H); ESI MS m/z=517.3 [M+H]⁺.

Ex. 20: Synthesis ofN—((S)-1-((3R,5′S)-5′-ethynyl-2-oxospiro[indoline-3,3′-pyrrolidin]-1′-yl)-4-fluoro-4-methyl-1-oxopentan-2-yl)-3-(trifluoromethoxy)benzamide

The title compound was prepared according to the procedure for Ex. 1,except that 3-(trifluoromethoxy)benzoic acid was used in place of5-(methylsulfonyl)-1H-indole-2-carboxylic acid in Step 9. ¹HNMR(acetone-d6, 400 MHz, PPM): δ 9.69 (s, 1H), 8.09 (d, J=8.5 Hz, 1H), 7.86(dt, J=7.7, 1.3 Hz, 1H), 7.70-7.75 (m, 1H), 7.62 (t, J=8.0 Hz, 1H),7.52-7.55 (m, 1H), 7.16 (td, J=7.7, 1.3 Hz, 1H), 6.94-7.04 (m, 2H), 6.82(td, J=7.6, 1.1 Hz, 1H). 5.04-5.13 (m, 2H), 4.37 (d, J=10.5 Hz, 1H),3.94 (d, J=10.4 Hz, 1H), 2.91 (d, J=2.1 Hz, 1H), 2.53-2.62 (m, 2H),2.18-2.38 (m, 2H), 1.49 (d, J=1.6 Hz, 3H), 1.44 (d, J=1.7 Hz, 3H); ESIMS m/z=530.2 [M−H]⁻.

Ex. 21: Synthesis of2,6-dichloro-N—((S)-1-((3R,5′S)-5′-ethynyl-2-oxospiro[indoline-3,3′-pyrrolidin]-1′-yl)-4-fluoro-4-methyl-1-oxopentan-2-yl)benzamide

The title compound was prepared according to the procedure for Ex. 1,except that 2,6-dichlorobenzoic acid was used in place of5-(methylsulfonyl)-1H-indole-2-carboxylic acid in Step 9. ESI MSm/z=518.2 [M+H]⁺.

Biological Activity

SARS-CoV-2 3C-like (3CL) protease fluorescence assay (FRET): RecombinantSARS-CoV-2 3CL-protease was expressed and purified.TAMRA-SITSAVLQSGFRKMK-Dabcyl-OH peptide 3CLpro substrate wassynthesized. Black, low volume, round-bottom, 384 well microplates wereused. In a typical assay, 0.85 μL of test compound was dissolved in DMSOthen incubated with SARS-CoV-2 3CL-protease (10 nM) in 10 μL assaybuffer (50 mM HEPES [pH 7.5], 1 mM DTT, 0.01% BSA, 0.01% Triton-X 100)for 30 min at RT. Next, 10 μL of 3CL-protease substrate (40 μM) in assaybuffer was added and the assays were monitored continuously for 1 h inan Envision multimode plate reader operating in fluorescence kineticsmode with excitation at 540 nm and emission at 580 nm at RT. No compound(DMSO only) and no enzyme controls were routinely included in eachplate. All experiments were run in duplicate. Data Analysis: SARS-CoV-23CL-protease enzyme activity was measured as initial velocity of thelinear phase (RFU/s) and normalized to controlled samples DMSO (100%activity) and no enzyme (0% activity) to determine percent residualactivity at various concentrations of test compounds (0-10 μM). Datawere fitted to normalized activity (variable slope) versus concentrationfit in GraphPad Prism 7 to determine IC₅₀. All experiments were run induplicate, and IC₅₀ ranges are reported as follows: A<0.1 μM; B 0.1-1μM; C>1 μM.

TABLE 1 Summary of Activities FRET FRET Compound IC₅₀ Compound IC₅₀ 1 B2 B 3 B 4 A 5 A 6 B 7 A 8 A 9 A 10 B 11 A 12 A 13 A 14 B 15 A 16 B 17 C18 C 19 C 20 B 21 C

All references cited herein, whether in print, electronic, computerreadable storage media or other form, are expressly incorporated byreference in their entirety, including but not limited to, abstracts,articles, journals, publications, texts, treatises, internet web sites,databases, patents, and patent publications.

Various changes and modifications to the disclosed embodiments will beapparent to those skilled in the art and such changes and modificationsincluding, without limitation, those relating to the chemicalstructures, substituents, derivatives, formulations and/or methods ofthe invention may be made without departing from the spirit of theinvention and the scope of the appended claims.

Although the invention has been described with respect to variouspreferred embodiments, it is not intended to be limited thereto, butrather those skilled in the art will recognize that variations andmodifications may be made therein which are within the spirit of theinvention and the scope of the appended claims.

1. A compound represented by Formula (I)

or a pharmaceutically acceptable salt thereof, wherein: A is selected from: 1) —R₁₁; 2) —OR₁₂; and 3) —NR₁₃R₁₄; B is an optionally substituted aryl or optionally substituted heteroaryl; Q₁ is selected from: 1) Hydrogen; 2) Optionally substituted —C₁-C₈ alkyl; 3) Optionally substituted —C₃-C₈ cycloalkyl; 4) Optionally substituted 3- to 8-membered heterocyclic; 5) Optionally substituted aryl; 6) Optionally substituted —R₁₅S(O)₂R₁₆; 7) Optionally substituted —R₁₅C(O)R₁₆; 8) Optionally substituted —R₁₅C(O)OR₁₆; and 9) Optionally substituted —R₁₅C(O)NR₁₃; R₁, R₂, and R₃ are each independently selected from: 1) Hydrogen; 2) Optionally substituted —C₁-C₈ alkyl; 3) Optionally substituted —C₂-C₈ alkenyl; 4) Optionally substituted —C₂-C₈ alkynyl; 5) Optionally substituted —C₃-C₈ cycloalkyl; 6) Optionally substituted 3- to 8-membered heterocycloalkyl; 7) Optionally substituted aryl; 8) Optionally substituted arylalkyl; 9) Optionally substituted heteroaryl; and 10) Optionally substituted heteroarylalkyl; alternatively, R₁ and R₂ are taken together with the carbon atom to which they are attached to form an optionally substituted 3- to 8-membered carbocyclic ring or an optionally substituted 3- to 8-membered heterocyclic ring. R₄ is hydrogen, optionally substituted —C₁-C₄ alkyl, optionally substituted C₂-C₄-alkenyl, or optionally substituted —C₃-C₆ cycloalkyl. R₁₁ and R₁₂ are each independently selected from: 1) Optionally substituted —C₁-C₈ alkyl; 2) Optionally substituted —C₂-C₈ alkenyl; 3) Optionally substituted —C₂-C₈ alkynyl; 4) Optionally substituted —C₃-C₈ cycloalkyl; 5) Optionally substituted 3- to 8-membered heterocycloalkyl; 6) Optionally substituted aryl; 7) Optionally substituted arylalkyl; 8) Optionally substituted heteroaryl; and 9) Optionally substituted heteroarylalkyl; R₁₃ and R₁₄ each independently selected from: 1) Hydrogen; 2) Optionally substituted —C₁-C₈ alkyl; 3) Optionally substituted —C₂-C₈ alkenyl; 4) Optionally substituted —C₂-C₈ alkynyl; 5) Optionally substituted —C₃-C₈ cycloalkyl; 6) Optionally substituted 3- to 8-membered heterocycloalkyl; 7) Optionally substituted aryl; 8) Optionally substituted arylalkyl; 9) Optionally substituted heteroaryl; and 10) Optionally substituted heteroarylalkyl; alternatively, R₁₃ and R₁₄ are taken together with the nitrogen atom to which they are attached to form an optionally substituted 3- to 8-membered heterocyclic ring; R₁₅ is absent or optionally substituted —C₁-C₈ alkyl; and R₁₆ is selected from: 1) Optionally substituted —C₁-C₈ alkyl; 2) Optionally substituted —C₂-C₈ alkenyl; 3) Optionally substituted —C₂-C₈ alkynyl; 4) Optionally substituted —C₃-C₈ cycloalkyl; 5) Optionally substituted 3- to 8-membered heterocycloalkyl; 6) Optionally substituted aryl; 7) Optionally substituted arylalkyl; 8) Optionally substituted heteroaryl; and 9) Optionally substituted heteroarylalkyl.
 2. The compound of claim 1, wherein A is derived from one of the following by removal of a hydrogen atom, and optionally substituted:


3. The compound of claim 1, wherein R₁ is selected from one of the following:


4. The compound of claim 1, represented by Formula (III-1), or a pharmaceutically acceptable salt thereof:

wherein A, B, R₁, and R₃ are as defined in claim
 1. 5. The compound of claim 1, represented by Formula (V), or a pharmaceutically acceptable salt thereof:

wherein A, B, and R₁ are as defined in claim
 1. 6. The compound of claim 1, represented by Formula (X), or a pharmaceutically acceptable salt thereof:

wherein A, R₁, and R₃ are as defined in claim
 1. 7. The compound of claim 1, represented by one of Formulae (XII-1) to (XII-5), or a pharmaceutically acceptable salt thereof:

wherein each R₁₀ is independently selected from: 1) Halogen; 2) —CN; 3) —OR₁₃; 4) —SR₁₃; 5) —NR₁₃R₁₄; 6) —OC(O)NR₁₃R₁₄; 7) Optionally substituted —C₁-C₆ alkyl; 8) Optionally substituted —C₃-C₈ cycloalkyl; 9) Optionally substituted 3- to 8-membered heterocycloalkyl; 10) Optionally substituted aryl; and 11) Optionally substituted heteroaryl; m is 0, 1, 2, 3, or 4; R₁, and R₃ are as defined in claim
 1. 8. The compound of claim 1, selected from the compounds set forth below: Compound Structure 1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21


9. A pharmaceutical composition comprising a compound according to claim 1 and a pharmaceutically acceptable carrier or excipient.
 10. A method of treating or preventing a virus infection in a subject susceptible to or suffering from the virus infection, the method comprising administering to the subject an effective amount of a compound according to claim
 1. 11. A method of treating or preventing a coronavirus infection in a subject in need thereof, comprising administering to the subject a therapeutically effective amount of a compound according to claim
 1. 12. The method according to claim 11, wherein the coronavirus selected from a 229E, NL63, OC43, HKU1, SARS-CoV or a MERS coronavirus.
 13. A method of inhibiting viral 3C protease or viral 3CL protease in a subject, comprising administering to said subject an effective amount of a compound according to claim
 1. 14. The method according to claim 13, wherein the subject is a human.
 15. A method of treating a respiratory disorder in a subject in need thereof, comprising administering to the subject a therapeutically effective amount of a compound of claim
 1. 16. The method according to claim 15, wherein the compound or pharmaceutical composition is administered orally, subcutaneously, intravenously or by inhalation. 